Test Procedure

DH1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Are DTCs P0068, P0121, P0122, P0123, P1120, or P1124 present?

Yes	No
For DTC P0068, GO to DH18. For DTC P0121, GO to DH24. For KOEO and KOER DTC P0122, GO to DH14. For continuous memory DTC P0122, GO to DH13. For DTC P0123, GO to DH9. For DTC P1120, GO to DH4. For DTC P1124, GO to DH2.	For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .

DH2 KOEO AND KOER DTC P1124: CHECK FOR ANY OTHER DTC

Clear the DTCs.
Carry out the PCM self-test.

Is DTC P0405 present?

Yes	No
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .	GO to DH3.

DH3 CHECK FOR A STUCK THROTTLE PLATE OR LINKAGE

Ignition OFF.
Visually inspect the throttle linkage and throttle plate for binding or sticking.
Verify the throttle plate and linkage is at closed throttle position.

Does the throttle move freely and return to a closed throttle position?

Yes	No
The throttle plate and linkage are OK. GO to DH9.	REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

DH4 DTC P1120: CHECK THE TP CIRCUIT FOR FRAYED WIRES OR CORROSION ON THE CONNECTORS

Ignition OFF.
Carry out a visual inspection of the pins on the harness connector at the TP sensor for corrosion.
Carry out a visual inspection of the harness wires between the TP sensor and the PCM for insulation fraying and corrosion.

Is a concern present?

Yes	No
REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.	GO to DH5.

DH5 CHECK FOR A STUCK TP SENSOR

Ignition ON, engine OFF.
Slowly move the throttle from the closed throttle position to the wide open throttle position and observe the TP PID.
Access the PCM and monitor the TP PID.

Is the voltage greater than 4.5 V?

Yes	No
GO to DH22.	GO to DH6.

DH6 CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE TP SENSOR HARNESS CONNECTOR

TP Sensor connector disconnected.
Ignition ON, engine OFF.

Measure the voltage between:

(+) TP Sensor Connector, Harness Side	(-) TP Sensor Connector, Harness Side
VREF	SIGRTN

Is the voltage between 4.5 - 5.5 V?

Yes	No
GO to DH7.	GO to PINPOINT TEST C .

DH7 CHECK THE TP CIRCUIT FOR AN OPEN IN THE HARNESS

Ignition OFF.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) TP Sensor Connector, Harness Side
TP - Pin E61	TP

Is the resistance less than 5 ohms?

Yes	No
GO to DH8.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DH8 CHECK THE TP SENSOR VOLTAGE TO THE PCM

PCM connector connected.
TP Sensor connector connected.
Ignition ON, engine running.
Idle the engine for 2 minutes.
Ignition OFF.
Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.
Slowly move the throttle from the closed throttle position to the wide open throttle position and observe the TP PID.

Is the voltage between 0.17 - 0.49 V?

Yes	No
INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.	If DTC P1120 is still present, GO to DH22.

DH9 DTC P0123 OR DTC P1124: INDUCE THE OPPOSITE TP SENSOR VOLTAGE

TP Sensor connector disconnected.
Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.

Is the voltage less than 0.17 V?

Yes	No
GO to DH10.	GO to DH11.

DH10 CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE TP SENSOR VEHICLE HARNESS CONNECTOR

Ignition ON, engine OFF.

Measure the voltage between:

(+) TP Sensor Connector, Harness Side	(-) TP Sensor Connector, Harness Side
VREF	SIGRTN

Is the voltage between 4.5 - 5.5 V?

Yes	No
INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.	GO to PINPOINT TEST C .

DH11 CHECK THE CIRCUIT FOR A SHORT TO VREF AND VPWR IN THE HARNESS

Ignition OFF.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
VPWR - Pin B35	TP - Pin E61
VREF - Pin E57	TP - Pin E61

Are the resistances greater than 10K ohms?

Yes	No
GO to DH12.	REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

DH12 CHECK FOR AN INTERMITTENT SHORT TO VOLTAGE IN THE TP CIRCUIT

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
VPWR - Pin B35, B36	TP - Pin E61
VREF - Pin B40, E57	TP - Pin E61

Observe the digital multimeter (DMM) for an indication of a concern while shaking, wiggling, and bending the TP circuit between the TP sensor and the PCM.

Is a concern present?

Yes	No
REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.	GO to DH26.

DH13 CONTINUOUS MEMORY DTC P0122: CHECK THE TP CIRCUIT FOR AN INTERMITTENT CONCERN

Ignition ON, engine OFF.
Clear the PCM DTCs.
Ignition ON, engine running.
Retrieve the continuous memory DTCs.

Is DTC P0122 present?

Yes	No
GO to DH14.	GO to PINPOINT TEST Z .

DH14 KOEO AND KOER DTC P0122: CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE TP SENSOR VEHICLE HARNESS CONNECTOR

Ignition OFF.
TP Sensor connector disconnected.
Ignition ON, engine OFF.

Measure the voltage between:

(+) TP Sensor Connector, Harness Side	(-) TP Sensor Connector, Harness Side
VREF	SIGRTN

Is the voltage between 4.5 - 5.5 V?

Yes	No
GO to DH15.	GO to PINPOINT TEST C .

DH15 CHECK THE TP CIRCUIT FOR AN OPEN IN THE HARNESS

Ignition OFF.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) TP Sensor Connector, Harness Side
TP - Pin E61	TP

Is the resistance less than 5 ohms?

Yes	No
GO to DH16.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DH16 CHECK THE TP CIRCUIT FOR A SHORT TO PWRGND OR SIGRTN IN THE HARNESS

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
TP - Pin E61	PWRGND - Pin B47, B48, B49, B50
TP - Pin E61	SIGRTN - Pin E58

Are the resistances greater than 10K ohms?

Yes	No
GO to DH17.	REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

DH17 INDUCE THE OPPOSITE TP SENSOR VOLTAGE

PCM connector connected.

Connect a 5 amp fused jumper wire between the following:

Point A TP Sensor Connector, Harness Side	Point B TP Sensor Connector, Harness Side
VREF	TP

Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.

Is the voltage greater than 4.65 V?

Yes	No
INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.	GO to DH26.

DH18 DTC P0068: CHECK THE RATIONALITY BETWEEN THE TP AND MAF SENSORS

Attempt to start the engine.

Does the engine start?

Yes	No
GO to DH19.	CHECK for major leaks, cracks and openings between the MAF sensor and the throttle body. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. If OK, GO to PINPOINT TEST A .

DH19 CHECK THE TP SENSOR FOR MECHANICAL OPERATION

Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.
Slowly move the throttle from the closed throttle position to the wide open throttle position and observe the TP PID.

Is the voltage between 0.49 - 4.65 V?

Yes	No
GO to DH20.	INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.

DH20 CHECK THE TP SENSOR SIGNAL HIGH VERSUS THE ENGINE LOAD WHILE DRIVING THE VEHICLE

Ignition ON, engine running.
Access the PCM and monitor the TP PID.
Access the PCM and monitor the LOAD PID.
Drive the vehicle, exercising the throttle and TP sensor.

Is the TP PID greater than 2.44 volts and the LOAD PID less than 30%?

Yes	No
LISTEN for air noise around the MAF sensor and throttle body while the engine is running. REPAIR as necessary. If OK, INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.	GO to DH21.

DH21 CHECK THE TP SENSOR SIGNAL LOW VERSUS THE ENGINE LOAD WHILE DRIVING THE VEHICLE

Ignition ON, engine running.
Access the PCM and monitor the TP PID.
Access the PCM and monitor the LOAD PID.
Drive the vehicle while exercising the throttle and TP sensor near higher gears (preferably overdrive).

Is the TP PID less than 0.24 volt and the LOAD PID greater than 55%?

Yes	No
If continuous memory DTC P0068 is present, INSTALL a new MAF sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.	Unable to duplicate or identify the concern at this time. GO to PINPOINT TEST Z .

DH22 CHECK FOR AN INTERMITTENT TP SIGNAL

Ignition ON, engine running.
Access the PCM and monitor the TP PID.
Increase the engine speed to 1,500 RPM for 10 seconds.
Lightly tap on the TP sensor and wiggle the harness connector to simulate road shock.

Is the voltage between 0.49 V - 4.65 V?

Yes	No
GO to DH23.	INSPECT the TP sensor connector. REPAIR as necessary. If OK, INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.

DH23 CHECK THE TP SENSOR HARNESS FOR INTERMITTENT OPENS OR SHORTS

Ignition OFF.
Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.
Grasp the vehicle harness closest to the TP sensor connector.
Shake and bend a small section of the harness all the way to the bulkhead.
Wiggle, shake, and bend the harness from the bulkhead to the PCM.

Is the voltage between 0.49 V - 4.65 V?

Yes	No
Unable to duplicate or identify the concern at this time. GO to PINPOINT TEST Z .	ISOLATE the concern and REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

DH24 DTC P0121: CHECK FOR OBSTRUCTION OR STICKING CONCERNS

Do not attempt to clean the throttle bore and plate area. Cleaning damages the throttle body assembly.

NOTE: Conditions of sticking or obstruction can either be within the cables or throttle body assembly.

Disconnect the accelerator cable and speed control cable from the throttle body linkage.
Rotate the throttle body linkage.

Does the throttle body rotate freely without a sticking, binding, or grabbing condition?

Yes	No
INSPECT the cable(s). REPAIR as necessary. REPEAT the self-test. If DTC P0121 is still present, GO to DH25.	INSTALL a new throttle body assembly. REFER to the appropriate Fuel Charging And Controls article . CLEAR the DTCs. REPEAT the self-test.

DH25 CHECK THE FUNCTIONALITY OF THE THROTTLE POSITION SENSOR

Ignition ON, engine OFF.
Access the PCM and monitor the TP PID.
While slowly pressing the accelerator from the closed throttle position to the wide open throttle position, observe the TP PID.

Does the TP PID display a smooth reading during accelerator movement?

Yes	No
Unable to duplicate or identify the concern at this time. GO to PINPOINT TEST Z .	INSTALL a new TP sensor. REFER to the appropriate Electronic Engine Controls article . CLEAR the DTCs. REPEAT the self-test.

DH26 CHECK FOR CORRECT PCM OPERATION

Disconnect all the PCM connectors.
Visually inspect for:
- pushed out pins
- corrosion
Connect all the PCM connectors and make sure they seat correctly.
Carry out the PCM self-test and verify the concern is still present.

Is the concern still present?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , Programming the VID Block for a Replacement PCM.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.