2007 ISUZU KB P190 heater
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Engine Management – V6 – Diagnostics Page 6C1-2–50
7 Diagnostic Trouble Code Tables
7.1 DTC List
As a number of diagnostic tables cater for multiple DTC numbers, a specific DTC table may be difficult to locate.
To make a specific DTC diagnostic table easier to find, the next list is arranged in numerical ascending order.
The actual diagnostic table can be located by selecting the link provided.
DTC Description Diagnostic Table
P0008 Engine Position System Performance (Bank 1) 7.2 DTC P0008, P0009 or P0016
P0009 Engine Position System Performance (Bank 2) 7.2 DTC P0008, P0009 or P0016
P0016 Crankshaft / Intake Camshaft Position not Plausible
(Bank 1) 7.2 DTC P0008, P0009 or P0016
P0030 O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036,
P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0031 O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0032 O2 Sensor Heater Circuit High Voltage (Bank 1, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0036 O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0037 O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0038 O2 Sensor Heater Circuit High Voltage (Bank 1, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0040 O2 Sensor Signals Not Plausible (Bank 1, Sensor 1 & Bank 2, Sensor 1) 7.4 DTC P0040 or P0041
P0041 O2 Sensor Signals Not Plausible (Bank 1, Sensor 2 &
Bank 2, Sensor 2) 7.4 DTC P0040 or P0041
P0050 O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036,
P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0051 O2 Sensor Heater Circuit Low Voltage (Bank 2, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0052 O2 Sensor Heater Circuit High Voltage (Bank 2, Sensor 1) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0053 O2 Sensor Heater Resistance Range / Performance (Bank 1, Sensor 1) 7.5 DTC P0053 or P0059
P0056 O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036,
P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0057 O2 Sensor Heater Circuit Low Voltage (Bank 2, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
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Engine Management – V6 – Diagnostics Page 6C1-2–51
DTC Description Diagnostic Table
P0058 O2 Sensor Heater Circuit High Voltage (Bank 2, Sensor 2) 7.3 DTC P0030, P0031, P0032, P0036,
P0037, P0038, P0050, P0051, P0052,
P0056, P0057 or P0058
P0059 O2 Sensor Heater Resistance Range / Performance (Bank 2, Sensor 1) 7.5 DTC P0053 or P0059
P0101 Mass Air Flow Sensor Circuit Range / Performance 7.6 DTC P0101, P0102 or P0103
P0102 Mass Air Flow Sensor Voltage Low
7.6 DTC P0101, P0102 or P0103
P0103 Mass Air Flow Sensor Voltage High 7.6 DTC P0101, P0102 or P0103
P0112 Intake Air Temperature Sensor Circuit Low Voltage 7.7 DTC P0112 or P0113
P0113 Intake Air Temperature Sensor Circuit High Voltage 7.7 DTC P0112 or P0113
P0116 Engine Coolant Temperature Sensor Circuit Range /
Performance 7.8 DTC P0116, P0117, P0118, P0125 or
P1258
P0117 Engine Coolant Temperature Sensor Circuit Low Voltage 7.8 DTC P0116, P0117, P0118, P0125 or P1258
P0118 Engine Coolant Temperature Sensor Circuit High Voltage 7.8 DTC P0116, P0117, P0118, P0125 or P1258
P0121 Throttle Position Sensor 1 Circuit Range / Performance 7.9 DTC P0121, P0122, P0123, P0221, P0222,or P0223
P0122 Throttle Position Sensor 1 Circuit Low Voltage 7.9 DTC P0121, P0122, P0123, P0221,
P0222,or P0223
P0123 Throttle Position Sensor 1 Circuit High Voltage 7.9 DTC P0121, P0122, P0123, P0221,
P0222,or P0223
P0125 Insufficient Engine Coolant Temperature For Closed Loop Fuel Control 7.8 DTC P0116, P0117, P0118, P0125 or
P1258
P0130 O2 Sensor Circuit Malfunction (Bank 1, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0131 O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) 7.11 DTC P0133 or P0153
P0135 O2 Sensor Heater Circuit Range / Performance (Bank 1, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0137 O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
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ISUZU KB P190 2007
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Engine Management – V6 – Diagnostics Page 6C1-2–52
DTC Description Diagnostic Table
P0138 O2 Sensor Circuit High Voltage (Bank 1, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0139 O2 Sensor Slow Response (Bank1 Sensor 2) 7.12 DTC P0139 or P0159
P0140 O2 Sensor Circuit No Activity Detected (Bank 1
Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0141 O2 Sensor Heater Circuit Range / Performance (Bank 1, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0150 O2 Sensor Circuit Malfunction (Bank 2, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0151 O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0152 O2 Sensor Circuit High Voltage (Bank 2, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0153 O2 Sensor Circuit Slow Response (Bank 2 Sensor 1) 7.11 DTC P0133 or P0153
P0155 O2 Sensor Heater Circuit Range / Performance (Bank 2, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0157 O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0158 O2 Sensor Circuit High Voltage (Bank 2, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0159 O2 Sensor Slow Response (Bank1 Sensor 2) 7.12 DTC P0139 or P0159
P0160 O2 Sensor Circuit No Activity Detected (Bank 2, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P0161 O2 Sensor Heater Circuit Range / Performance (Bank 2, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
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Engine Management – V6 – Diagnostics Page 6C1-2–58
DTC Description Diagnostic Table
P2189 Fuel Trim Lean during Idling/Deceleration (Bank 2) 7.53 DTC P2187 or P2189
P2190 Fuel Trim Rich during Idling/Deceleration (Bank 2) 7.54 DTC P2188 or P2190
P2195 B1S1 O2 Sensor – System Too Lean (Bank 1 Sensor 1) 7.55 DTC P2195 or P2197
P2196 B1S1 O2 Sensor – System Too Rich (Bank 1 Sensor 1) 7.56 P2196 or P2198
P2197 B2S1 O2 Sensor – System Too Lean (Bank 2 Sensor 1) 7.55 DTC P2195 or P2197
P2198 B2S1 O2 Sensor – System Too Rich (Bank 2 Sensor 1) 7.56 P2196 or P2198
P2227 Barometric Pressure Sensor Range / Performance 7.57 DTC P2227, P2228 or P2229
P2228 Barometric Pressure Sensor Voltage Low 7.57 DTC P2227, P2228 or P2229
P2229 Barometric Pressure Sensor Voltage High 7.57 DTC P2227, P2228 or P2229
P2231 O2 Sensor Signal Interference by Heater Circuit (Bank 1,
Sensor 1) 7.58 DTC P2231, P2232, P2234, P2235, P2251
or P2254
P2232 O2 Sensor Signal Short to Heater Circuit (Bank 1 Sensor 2) 7.58 DTC P2231, P2232, P2234, P2235, P2251
or P2254
P2234 O2 Sensor Signal Interference by Heater Circuit (Bank 2, Sensor 1) 7.58 DTC P2231, P2232, P2234, P2235, P2251
or P2254
P2235 O2 Sensor Signal Short to Heater Circuit (Bank 2 Sensor 2) 7.58 DTC P2231, P2232, P2234, P2235, P2251
or P2254
P2237 O2 Sensor Pump Current Circuit Malfunction (Bank 1, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2238 O2 Sensor Pump Current Circuit Low Voltage (Bank 1, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2239 O2 Sensor Pump Current Circuit High Voltage (Bank 1, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2240 O2 Sensor Pump Current Circuit Malfunction (Bank 2, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2241 O2 Sensor Pump Current Circuit Low Voltage (Bank 2, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2242 O2 Sensor Pump Current Circuit High Voltage (Bank 2, Sensor 1) 7.59 DTC P2237, P2238, P2239, P2240, P2241
or P2242
P2243 O2 Sensor Voltage Signal Circuit Malfunction (Bank 1, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P2247 O2 Sensor Voltage Signal Circuit Malfunction (Bank 2, Sensor 1) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
P2251 O2 Sensor Ground Circuit Malfunction (Bank 1, Sensor 1) 7.58 DTC P2231, P2232, P2234, P2235, P2251 or P2254
P2254 O2 Sensor Ground Circuit Malfunction (Bank 2, Sensor 1) 7.58 DTC P2231, P2232, P2234, P2235, P2251 or P2254
P2270 O2 Sensor Lean / Rich Switch Signal Malfunction (Bank 1, Sensor 2) 7.10 DTC P0130, P0131, P0132, P0135,
P0137, P0138, P0140, P0141, P0150
P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270,
P2271, P2272, P2273, P2297 or P2298
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ISUZU KB P190 2007
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Engine Management – V6 – Diagnostics Page 6C1-2–62
DTC P0008, P0009 or P0016 Diagnostic Table
Step Action Yes No
1 1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Start the engine.
3 Allow the engine to reach the normal operating temperature.
4 Increase the engine speed to 2,000 rpm for 10 seconds.
5 Using Tech 2, select the DTC display function.
Does DTC P0008, P0009 or P0016 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Are DTCs relating to the following DTCs also set:
• Camshaft actuator circuit
• CMP sensor circuit
• CKP sensor circuit Go to the
appropriate DTC
Table in this Section Go to Step 4
4 1 Inspect the engine for the following fault conditions. Refer to
6A1 Engine Mechanical – V6:
• incorrect installation of the CMP sensor,
• incorrect installation of the CKP sensor,
• timing chain tensioner fault condition,
• incorrectly installed timing chain,
• excessive play in the timing chain, and
• timing chain that jumped teeth.
W as any fault found and rectified? Go to Step 5 Refer to Additional
Information in this DTC
5 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does any of the crankshaft / camshaft position correlation DTCs fail
this ignition cycle? Go to Step 2 Go to Step 6
6 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.3 DTC P0030, P0031, P0032, P0036, P0037,
P0038, P0050, P0051, P0052, P0056,
P0057 or P0058
DTC Descriptor
This diagnostic procedure supports the following DTCs:
• DTC P0030 – O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
• DTC P0031 – O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 1)
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Engine Management – V6 – Diagnostics Page 6C1-2–63
• DTC P0032 – O2 Sensor Heater Circuit High Voltage (Bank 1, Sensor 1)
• DTC P0036 – O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
• DTC P0037 – O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 2)
• DTC P0038 – O2 Sensor Heater Circuit High Voltage (Bank 1, Sensor 2)
• DTC P0050 – O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 1)
• DTC P0051 – O2 Sensor Heater Circuit Low Voltage (Bank 2, Sensor 1)
• DTC P0052 – O2 Sensor Heater Circuit High Voltage (Bank 2, Sensor 1)
• DTC P0056 – O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2)
• DTC P0057 – O2 Sensor Heater Circuit Low Voltage (Bank 2, Sensor 2)
• DTC P0058 – O2 Sensor Heater Circuit High Voltage (Bank 2, Sensor 2)
Circuit Description
The engine control relay applies positive voltage to the heater ignition voltage circuits of the HO2S. The ECM applies a
pulse width modulated (PW M) ground to the heater control circuit of the HO2S through a device within the ECM called a
driver, to control the HO2S rate of heating.
The driver has a feedback circuit that is pulled-up when the voltage is approximately 3.3 V. The ECM monitors the driver
feedback circuit to determine if the control circuit is open, shorted to ground or shorted to a positive voltage.
An HO2S heater control circuit DTC sets if the ECM detects a high resistance, open circuit, short to ground or short to
voltage fault condition in the HO2S heater control circuit.
Conditions for Running the DTC
Runs continuously once the following conditions are met:
• The ignition voltage is 10.0 – 16.0 V.
• Engine speed is greater than 80 rpm
Conditions for Setting the DTC
DTC P0030, P0036, P0050 or P0056
The ECM detects an open circuit fault condition in the HO2S heater control circuit when the HO2S heater is commanded
off.
DTC P0031, P0037, P0051 or P0057
The ECM detects a short to ground fault condition in the HO2S heater control circuit when the HO2S heater is
commanded off.
DTC P0032, P0038, P0052 or P0058
The ECM detects a short to voltage fault condition in the HO2S heater control circuit for five seconds when the HO2S
heater is commanded on.
Conditions for Clearing the DTC
The HO2S heater control circuit DTCs are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for
action taken when Type B DTC sets and conditions for clearing Type B DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the HO2S system operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• A faulty HO2S heater element may cause an open heater circuit condition. This fault may be intermittent or only
show up after the sensor has operated for a period.
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Engine Management – V6 – Diagnostics Page 6C1-2–64
• Inspect the HO2S wiring harness for contact with the exhaust system.
• The front and the rear HO2Ss have a separate fuse connection. If both front or both the rear DTCs are set, the
appropriate HO2S ignition voltage circuit may be open.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
Test Description
The following number refers to the step number in the diagnostic table:
4 The ECM monitors the driver feedback circuit to determine if the heater control circuit is open, shorted to ground or shorted to a positive voltage. If the voltage is outside the specified range, there is a fault condition with the heater
control circuit.
DTC P0030 to P0032, P0036 to P0038, P0050 to P0052 and P0056 to P0058 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Start the engine.
3 Allow the engine to run at idle speed for at least 30 seconds.
4 Increase the engine speed to 2,000 rpm for 10 seconds.
5 Using Tech 2, select the DTC display function.
Does DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050,
P0051, P0052, P0056, P0057 or P0058 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Disconnect the appropriate HO2S wiring connector.
2 Switch on the ignition with the engine not running.
3 Connect a test lamp between the HO2S heater ignition voltage circuit and the ECM housing.
Does the test lamp illuminate? Go to Step 4 Go to Step 5
4 Using a digital multimeter, measure the voltage between the HO2S
heater control circuit and a good ground.
Does the multimeter display:
• HO2S 1: 4.6 – 5.2 V?
• HO2S 2: 2.8 – 4.2 V? Go to Step 7 Go to Step 6
5
NOTE
The HO2S ignition voltage circuit is shared with other
sensors. Ensure that all circuits and components that
share this ignition voltage circuit are tested for a short to
ground.
Repair the high resistance open circuit or short to ground fault
condition in the HO2S heater ignition voltage circuit. Refer to 8A
Electrical - Body and Chassis for information on electrical wiring
repair procedures.
W as the repair completed? Go to Step 9 —
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ISUZU KB P190 2007
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Engine Management – V6 – Diagnostics Page 6C1-2–65
Step Action Yes No
6 Test the HO2S heater control circuit for a high resistance, open
circuit, short to ground or short to voltage fault condition. Refer to 8A
Electrical - Body and Chassis for information on electrical fault
diagnosis.
W as any fault found and rectified? Go to Step 9 Go to Step 8
7 Replace the appropriate HO2S. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
W as the repair completed? Go to Step 9 —
8 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 9 —
9 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does any of the HO2S heater control circuit DTCs fail this ignition
cycle? Go to Step 2 Go to Step 10
10 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.4 DTC P0040 or P0041
DTC Descriptor
This diagnostic procedure supports the following DTCs:
• DTC P0040 – O2 Sensor Signals Not Plausible (Bank 1, Sensor 1 & Bank 2, Sensor 1)
• DTC P0041 – O2 Sensor Signals Not Plausible (Bank 1, Sensor 2 & Bank 2, Sensor 2)
Circuit Description
The engine control relay applies positive voltage to the heater ignition voltage circuits of the HO2S. The ECM applies a
pulse width modulated (PW M) ground to the heater control circuit of the HO2S through a device within the ECM called a
driver, to control the HO2S rate of heating.
The ECM applies a voltage of approximately 450 mV between the reference signal circuit and low reference circuit of the
HO2S while the sensor temperature is less than the operating range.
Once the HO2S reaches operating temperature, the sensor varies this reference signal voltage, which constantly
fluctuates between the high voltage output and the low voltage output.
• The low voltage output is 0 – 450 mV, which occurs if the air fuel mixture is lean.
• The high voltage output is 450 – 1,000 mV, which occurs if the air fuel mixture is rich.
The ECM monitors, stores and evaluates the HO2S voltage fluctuation information to determine the level of oxygen
concentration in the exhaust.
An HO2S signal not plausible or wire connector swapped DTC sets if the ECM detects the HO2S signal voltages are
heading in the opposite direction of what was commanded.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the HO2S system operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
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ISUZU KB P190 2007