Page 188 of 5267
5.(K243) O2 SENSOR 2/2 SIGNAL CIRCUIT
Remove the jump wire.
Ignition on, engine not running.
With the scan tool, monitor the O2 Sensor voltage.
Is the voltage above 4.8 volts?
Ye s>>
Go To 6
No>>
Check the (K243) O2 Sensor 2/2 Signal circuit for a open or
short to voltage. Inspect the O2 Sensor connector and the
PCM harness connector. If OK, replace and program the
Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.(K399) O2 SENSOR 2/2 HEATER CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between ground and the (K399) O2 Sensor 2/2
Heater Control circuit in the O2 Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short to ground in the (K399) O2 Sensor 2/2
Heater Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
Page 189 of 5267
7.(K904) O2 RETURN DOWNSTREAM CIRCUIT
Measure the voltage on the (K904) O2 Return Downstream circuit in the
O2 Sensor harness connector.
Is the voltage at 2.5 volts?
Ye s>>
Check the fuel system for contaminants.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Check the (K904) O2 Downstream Return circuit for a short
to ground, open, or short to voltage. Inspect the O2 Sensor
connector and the PCM harness connector. If OK, replace
and program the Powertrain Control Module per Service
Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 191 of 5267

When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
2/2O2SENSOR
(K342) O2 SENSOR 2/2 SIGNAL CIRCUIT
(K399) O2 SENSOR 2/2 HEATER CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 2/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 192 of 5267

3.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
AIR INDUCTION SYSTEM - must be free from leaks
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connectedtocorrectinjector
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.O2 SENSOR
Ignition on, engine not running.
Disconnect the 2/2 O2 Sensor harness connector.
With the scan tool, monitor the 2/2 O2 Sensor voltage.
The O2 Sensor voltage should read 5.0 volts on the scan tool with the
connector disconnected.
Using a jumper wire, jump the (K243) O2 Signal 2/2 circuit to the
(K904) O2 Return Downstream circuit in the O2 Sensor harness con-
nector.
NOTE: The voltage should drop from 5.0 volts to 2.5 volts with the
jumper wire in place.
Did the O2 Sensor volts change from 5.0 volts to 2.5 volts?
Ye s>>
Replace the O2 Sensor
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
Page 193 of 5267
5.(K243) O2 SENSOR 2/2 SIGNAL CIRCUIT
Remove the jump wire.
Ignition on, engine not running.
With the scan tool, monitor the 2/2 O2 Sensor voltage.
Is the voltage above 4.8 volts?
Ye s>>
Check the (K243) O2 Sensor 2/2 Signal circuit for an open
or short to battery voltage. Inspect the O2 Sensor connector
and the PCM harness connector. If OK, replace and pro-
gram the Powertrain Control Module per Service Informa-
tion.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
Page 194 of 5267

6.(K399) O2 SENSOR 2/2 HEATER CONTROL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance of the (K399) O2 Sensor 2/2 Heater Control cir-
cuit from the O2 Sensor harness connector to the appropriate terminal
of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K399) O2 Sensor 2/2 Heater Con-
trol circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
7.(K904) O2 RETURN DOWNSTREAM CIRCUIT
Measure the voltage on the (K904) O2 Return Downstream circuit in the
O2 Sensor harness connector.
Is the voltage at 2.5 volts?
Ye s>>
Check the fuel system for contaminants.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Check the (K904) O2 Downstream Return circuit for a short
to ground, open, or short to voltage. Inspect the O2 Sensor
connector and the PCM harness connector. If OK, replace
and program the Powertrain Control Module per Service
Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 202 of 5267

P2101-ELECTRONIC THROTTLE CONTROL MOTOR PERFORMANCE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
With the vehicle running, ETC Motor not in Limp Home mode, and the TPS adaptation is complete.
Set Condition:
The PCM recognizes too large of an error between the actual position of the Throttle Plate and the Set Point
position. One trip fault and the code will set within 5 seconds. Three good trips to turn off the MIL ETC light is
flashing.
Possible Causes
THROTTLE BODY ASSEMBLY
LOW BATTERY VOLTAGE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Before continuing visually inspect the throttle blade and bore for any obstructions. Icing of the throt-
tlebodymayhavecausedthiscodetoset.
NOTE: Low battery voltage can also cause excessive current draw, in very hot and very cold ambient tem-
perature. Make sure the battery can pass a Load test before continuing.
NOTE: Diagnose any 5-Volt Supply, Battery, and TP Sensor DTCs before continuing.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.THROTTLE PLATE INSPECTION
Turn the ignition off.
Remove the Air Cleaner Assembly from the Throttle Body.
Check for any signs of a foreign material (ice or dirt) on the Throttle Plateor in the bore causing the Throttle Plate
to stick.
Manually open and close the throttle plate using your hands.
Does the Throttle Plate move?
Ye s>>
Go To 3
No>>
Remove the debris if possible or replace the Throttle Body Assembly. Disconnect the Battery when
replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC
RELEARN function.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 207 of 5267

When Monitored:
Ignition on and ETC motor is working.
Set Condition:
When the PCM requests to limit engine speed if PWM is too high for 20.5 seconds and before P2118 sets.
One trip fault and the code will set within 5 seconds. ETC light is illuminated.
Possible Causes
THROTTLE PLATE STUCK
(K447) ETC POSITIVE CIRCUIT OPEN
(K448) ETC NEGATIVE CIRCUIT OPEN
(K447) ETC POSITIVE CIRCUIT SHORTED TO GROUND
(K448) ETC NEGATIVE CIRCUIT SHORTED TO GROUND
ETC MOTOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool read DTCs.
In the Freeze Frame data, look at the temperature at which the fault occurred. If it occurred in extreme cold tem-
peratures, Icing of the throttle body may have caused this code to set.
NOTE: Diagnose any TP Sensor faults, 5-Volt Supply faults, and Battery Voltage High or Low DTCs before
continuing.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.THROTTLE PLATE STUCK
Turn the ignition off.
Remove the Air Cleaner Assembly from the Throttle Body.
Check for any signs of a foreign material (ice or dirt) causing the Throttleto stick.
Manually open and close the throttle plate using your hands.
Does the Throttle Plate move?
Ye s>>
Go To 3
No>>
Remove the debris if possible or replace the Throttle Body Assembly if signs of physical damage are
present. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is com-
plete, use a scan tool and select the ETC RELEARN function.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)