Clutch Pedal Position (CPP) Switch

1997 PCED OBDII-Diesel

SECTION 5C: Pinpoint Tests

N: Clutch Pedal Position (CPP) Switch

N1 DIAGNOSTIC TROUBLE CODE (DTC) P0704: CHECK PID CPP WITH NGS TESTER

Note: When performing KOER switch test, wait five seconds after pressing the trigger to start the test before running through the driver operated controls. The test may also take up to five minutes to complete.

No PID transition indicates a CPP circuit failure.
Key on, engine off.
Foot off clutch pedal.

Does PID read ON only?

Yes	No
GO to N2.	GO to N4.

N2 CHECK FOR CPP SWITCH FAILED CLOSED

Key on, engine off.
Unplug CPP switch.

Does PID go to OFF?

Yes	No
REPLACE CPP switch. CONFIRM fix with NGS Tester PID CPP.	GO to N3.

N3 CHECK FOR SHORT TO B+ IN CIRCUIT 306 (T/LB)

CPP switch unplugged.
Key off.
Unplug PCM.
Key on.
Measure voltage between Circuit 306 (T/LB) CPP connector contact and chassis ground.

Is B+ present?

Yes	No
SERVICE short to B+ in Circuit 306 (T/LB). REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.	Short to B+ is at Pin 29 in PCM. INSPECT PCM connector and pins. SERVICE as necessary. REASSEMBLE system. GO to N11.

N4 CHECK PID CPP

Hold clutch pedal to the floor.

Does PID read OFF only?

Yes	No
GO to N5.	Fault may be intermittent. GO to N12.

N5 CHECK FUSE 18 (10 AMP)

Check Fuse 18 (10 amp) in IP fuse panel.

Is Fuse 18 blown?

Yes	No
THROW away fuse. LOOK for short to ground. GO to N6.	LOOK for open circuit. GO to N8.

N6 CHECK CIRCUIT 296 (W/P) FOR SHORT TO GROUND

CPP switch unplugged.
Measure resistance between Circuit 296 (W/P) connector contact at CPP connector and chassis ground.

Is resistance less than 5 ohms?

Yes	No
SERVICE short to ground in Circuit 296 (W/P). REPLACE fuse. REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.	GO to N7.

N7 CHECK CIRCUIT 306 (T/LB) FOR SHORT TO GROUND

CPP switch unplugged.
Key off.
Unplug PCM.
Key on.
Measure resistance between Circuit 306 (T/LB) contact at CPP connector and chassis ground.

Is resistance less than 10,000 ohms?

Yes	No
SERVICE short to ground in Circuit 306 (T/LB). REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.	Short to ground is at PCM Pin 29. INSPECT PCM connector and PCM pins. SERVICE as necessary. REASSEMBLE system. GO to N11.

N8 CHECK CIRCUIT 296 (W/P) FOR OPEN

CPP switch unplugged.
Key off.
Measure resistance between Circuit 296 (W/P) connector contact at CPP connector and contact for Fuse 18.

Is resistance less than 5 ohms?

Yes	No
Circuit 296 (W/P) is OK. GO to N9.	SERVICE open in Circuit 296 (W/P). REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.

N9 CHECK CPP SWITCH FOR OPEN

CPP switch unplugged.
Key on.
Jumper between CPP connector contacts for Circuits 306 (T/LB) and 296 (W/P) (two middle pins).
Check NGS Tester PID CPP.

Does PID read ON?

Yes	No
REPLACE CPP switch. REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.	GO to N10.

N10 CHECK CIRCUIT 306 (T/LB) FOR OPEN

CPP switch unplugged.
Remove jumper between CPP connector contacts for Circuits 306 (T/LB) and 296 (W/P) (two middle pins).
Key off.
Unplug PCM.
Inspect 104-pin connector and repair as required.
Attach 104-pin breakout box.
Leave PCM disconnected.
Measure resistance between Test Pin 29 and switch contact for Circuit 306 (T/LB).

Is resistance less than 5 ohms?

Yes	No
Circuit 306 (T/LB) is OK. Open is at PCM Pin 29. INSPECT PCM connector and pins and REPAIR as required. REASSEMBLE system. GO to N11.	SERVICE open in Circuit 306 (T/LB). REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.

N11 CONFIRM PCM FAULT

Key on, engine off.
Check NGS Tester PID CPP.
Cycle clutch pedal.

Does PID switch between ON and OFF?

Yes	No
System is OK.	REPLACE PCM. CONFIRM fix with NGS Tester PID CPP. RUN self test.

N12 CHECKS FOR INTERMITTENT OPEN OR SHORT

CPP switch unplugged.
Key on.
Jumper between CPP connector contacts for Circuits 306 (T/LB) and 296 (W/P) (two middle pins).
Confirm that NGS Tester PID CPP shows ON.
Wiggle connectors and wires while watching CPP on NGS Tester.

Does PID switch between ON and OFF?

Yes	No
SERVICE circuitry at point of intermittent. REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP.	GO to N13.

N13 CHECK FOR INTERMITTENT SHORT TO B+

CPP switch unplugged.
Remove fuse.
Jumper between CPP connector contacts for Circuits 306 (T/LB) and 296 (W/P) (two middle pins).
Confirm that NGS Tester PID CPP shows OFF.
Wiggle connector and wires while watching CPP on NGS Tester.

Does PID switch between OFF and ON?

Yes	No
SERVICE circuitry at point of intermittent contact with B+ source. INSTALL fuse. REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP. RUN self test.	Intermittent not detected. REASSEMBLE system. CONFIRM fix with NGS Tester PID CPP. RUN self test.