2007 ISUZU KB P190 air condition

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-297
DTC P2621 or P2622 (Flash Code 94)
Circuit Description
The accelerator pedal position (APP) sensor is
mounted on the accelerator pedal control assembly.
The analogue APP signals are converted by the ECM
into a pulse width modulation (PWM) signal. This
converted signal is sent from the ECM to the TCM to
determine appropriate shift points depending on the
accelerator pedal pressing amount. If the ECM detects
an improper voltage level on the APP PWM signal
circuit, DTC P2621 or P2622 will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects a low voltage condition on the APP PWM signal circuit for longer than 3 seconds.
(DTC P2621) • The ECM detects a high voltage condition on the
APP PWM signal circuit for longer than 3 seconds.
(DTC P2622)
Action Taken When the DTC Sets • The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P2621
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition.
2. Back probe a DMM between the accelerator pedal position (APP) signal circuit of the TCM
harness connector (pin 16 of C-94) and a
known good ground.
3. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified value? 10.0 volts
Go to Step 6 Go to Step 4
4 Is the DMM voltage more than the specified value
at Step 3? 2.0 volts
Go to Step 7 Go to Step 5
5 Repair the short to ground between the ECM (pin
56 of C-58) and the TCM (pin 16 of C-94).
Did you complete the repair? —
Go to Step 11
—
61. Test the signal circuit between the ECM (pin
56 of C-58) and the TCM (pin 16 of C-94) for
an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 8

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ISUZU KB P190 2007

6E-298 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing DTC P2622
71. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
TCM (pin 16 of C-94).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
8 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
ECM (pin 56 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
9 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 11
—
10Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 11
—
111. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 12
12 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-299
31. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Connect a test lamp between the accelerator pedal position (APP) signal circuit of the TCM
harness connector (pin 16 of C-94) and a
known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 4 Go to Step 5
4 1. Test the signal circuit between the ECM (pin
56 of C-58) and the TCM (pin 16 of C-94) for a
short to battery or ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 7 Go to Step 6
5 Important:
Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 7
—
6Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 7
—
71. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition? —
Go to Step 3 Go to Step 8
8 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

6E-302 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
EGR Control System Check
Description
The EGR system recirculates a part of exhaust gas
back into the intake manifold, which results in reducing
NOx emissions. The EGR control system uses an
electronic control system to ensure both driveability
and low emission. A control current from the ECM
operates a solenoid to control the lift amount of EGR
valve. Also, an EGR position sensor is provided at the
rear of the solenoid to feed actual valve lift amount
back to the ECM for more precision control.
The EGR control starts when the conditions for engine
speed, engine coolant temperature, intake air
temperature and barometric pressure are satisfied.
Then, the valve opening is calculated according to the
engine speed, and target fuel injection quantity. Based
on this valve opening, the drive duty of the solenoid is
determined and the valve is driven accordingly. The
intake throttle valve is provided to adequate intake
manifold depression to ensure EGR gas flow. EGR Control Operation
• The engine coolant temperature (ECT) is between 5°C (41 °F) and 100 °C (212 °F).
• The intake air temperature (IAT) is more than 5 °C
(41 °F).
• The barometric pressure (BARO) is more than 90kPa (13psi).
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing EGR Control System Check
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with a scan tool.
Are any DTCs set in which the “Action Taken When
the DTC Sets” under that particular code states,
“The ECM inhibits EGR control”? —
Refer to Applicable DTC Go to Step 3

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-303
31. Inspect the following conditions:
• An EGR valve gasket that is missing ordamaged
• A sticking EGR valve
• EGR gas leakage any of the EGR passage between the exhaust manifold
and intake manifold
• Restricted or collapsed EGR passage between the exhaust manifold and the
EGR valve
• Any type of restriction in the exhaust system
• Restricted air cleaner element, restricted or collapsed air tubing between the air
cleaner and the intake manifold
• Any air induction leak
• Any water intrusion in the induction system
• Any contamination or objects that block the MAF sensor inlet
• Skewed or slow MAF sensor
• Skewed engine coolant temperature (ECT) sensor. Refer to Temperature vs
Resistance table to test the ECT sensor
at various temperature levels to evaluate
the possibility of a skewed sensor.
• Skewed barometric pressure (BARO) sensor. Determine the outside barometric
pressure from you location specified in
the altitude vs barometric pressure table.
Refer to Altitude vs Barometric Pressure.
• A sticking intake throttle valve
2. Repair the condition as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 4
4 1. Place the transmission in Neutral and set the
parking brake.
2. Start the engine and warm up (arrow engine coolant temperature to reach at least 60 °C
[140 °F]).
3. Accelerate the engine between idle and W.O.T (accelerator pedal full travel) many
times while observing the Desired EGR
Position and EGR Position parameter with a
scan tool.
Does the EGR Position parameter follow within the
specified value? ±
5%
Go to Step 5 Go to Step 8
5 1. Perform the EGR Solenoid Control with a scan
tool several times.
2. Command the Desired EGR Position Increase and Decrease while observing the EGR
Position.
Does the EGR Position parameter follow within the
specified value quick enough? ±
5%
Go to Step 6 Go to Step 8
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

6E-304 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
6Notice:
If the intake throttle solenoid is
commanded OFF, Intake Throttle Position
parameter indicates over 100%.
Observe the Desired Intake Throttle Position and
Intake Throttle Position parameter with a scan tool.
Does the Intake Throttle Position parameter follow
within the specified value? ±
5%
Go to Step 7 Go to Step 10
7 1. Perform the Intake Throttle Solenoid Control
with a scan tool several times.
2. Command the Desired Intake Throttle Position Increase and Decrease while observing the
Intake Throttle Position.
Does the Intake Throttle Position parameter follow
within the specified value quick enough? ±
5%
System OK Go to Step 10
8 1. Remove the EGR valve assembly from the
engine.
2. Inspect the EGR valve for the following conditions:
• Restricted EGR valve by foreign materials
• Excessive deposits at valve
• Bent valve shaft
3. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 9
9 1. Turn OFF the ignition.
2. Disconnect the EGR valve harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the EGR valve (pins 1, 2, 3, 4
and 6 of E-71).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 30, 31, 32, 62 and
63 of E-90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 12
10 1. Remove the intake duct that is connected to
the intake throttle valve.
2. Inspect the intake throttle valve for the following conditions:
• Restricted intake throttle valve by foreign materials
• Excessive deposits at throttle bore
• Bent butterfly valve
Notice: Replace the intake throttle valve is there is
any sticking
3. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 11
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-305
111. Turn OFF the ignition.
2. Disconnect the intake throttle valve harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the intake throttle valve (pins 1,
2, 3, 5 and 6 of E-38).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 35, 36, 55, 56 and
57 of E-90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 14 Go to Step 13
12 Replace the EGR valve. Refer to EGR valve
Replacement.
Did you complete the replacement? —
Go to Step 14
—
13Replace the intake throttle valve. Refer to Intake
Throttle Valve Replacement.
Did you complete the replacement? —
Go to Step 14
—
14Reconnect all previously disconnected components
or harness connector(s).
Did you complete the action? —
Go to Step 2
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-308 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing Glow Control System Check (2 of 2)
13Important
: The glow plugs may be burnt out if the
battery voltage supply circuit is shorted to a voltage
source.
Repair the short to battery or ignition voltage
between the glow relay (pin 1 of X-5) and the glow
plugs (E-49 terminal).
Did you complete the repair? —
Go to Step 17
—
141. Remove the glow relay.
2. Inspect for an intermittent and for poor connection on each glow relay terminal.
3. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 17 Go to Step 15
15 Replace the glow relay.
Did you complete the replacement? —
Go to Step 17
—
16Replace the appropriate glow plug.
Did you complete the replacement? —
Go to Step 17—
171. Reconnect all previously disconnected
components, relay, fuse or harness
connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the metal bus bar (glow plug power supply E-49 connector)
and a known good ground.
5. Perform the Glow Relay Control with a scan tool.
6. Command the relay ON while observing the test lamp.
Does the test lamp turn ON only when commanded
ON? —
Go to Step 5 Go to Step 2
Step
Action Value(s)Yes No
Step Action Value(s)Yes No
1 1. Turn OFF the ignition.
2. Inspect the Meter (10A) fuse in cabin fuse block.
Is the Meter (10A) fuse open? —
Go to Step 2 Go to Step 3
2 Replace the Meter (10A) fuse. If the fuse continues
to open, repair the short to ground on one of the
circuits that is fed by the Meter (10A) fuse or
replace the shorted attached component.
Did you complete the repair? —
Go to Step 14
—
31. Turn OFF the ignition.
2. Disconnect the ECM J-2 (C-58) harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the glow indicator lamp OFF? —
Go to Step 4 Go to Step 10

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ISUZU KB P190 2007