Test Procedure

B1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Are DTCs P0686, P0687, P0689, P0690, P2531, P2533 or P2535 present?

Yes	No
GO to B2.	RETURN to SYMPTOM CHARTS for further direction.

B2 CHECK FOR BCM DTCS

Carry out the BdyCM self-test.

Are any DTCs present?

Yes	No
REFER to the Multifunction Electronic Modules article to diagnose the BCM DTCs. Clear the PCM DTCs. REPEAT the self-test.	GO to B3.

B3 CHECK THE KEYST PIDS

Ignition ON, engine OFF.
Access the PCM and monitor the KEYST (MODE) PID.

Does the PID indicate ON?

Yes	No
GO to B6.	GO to B4.

B4 CHECK THE ISP-R CIRCUIT

Ignition OFF.
PCM connector disconnected.
Ignition ON, engine OFF.

Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
ISP-R - Pin B8	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to B5.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

B5 CHECK THE ISP-R CIRCUIT FOR A SHORT TO VOLTAGE

Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
ISP-R - Pin B8	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to B13.

B6 CHECK THE B+ VOLTAGE TO PCM POWER RELAY

Ignition OFF.
PCM Power Relay connector disconnected.

Measure the voltage between:

(+) PCM Power Relay Connector, Harness Side	(-)
B+ - Pin 1, 3	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to B7.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

B7 CHECK THE PCM POWER RELAY

PCM Power Relay connector disconnected.
Carry out the PCM power relay component test. Refer to the Component Testing article.

Is a concern present?

Yes	No
INSTALL a new PCM Power Relay. Clear the PCM DTCs. REPEAT the self-test.	GO to B8.

B8 CHECK THE PCMRC CIRCUIT FOR AN OPEN

Ignition OFF.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Power Relay Connector, Harness Side	(-) PCM Connector, Harness Side
PCMRC - Pin 2	PCMRC - Pin B1

Is the resistance less than 5 ohms?

Yes	No
GO to B9.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

B9 CHECK THE PCMRC CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

(+) PCM Power Relay Connector, Harness Side	(-)
PCMRC - Pin 2	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to B10.	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

B10 CHECK THE PCMRC CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.

Measure the voltage between:

(+) PCM Power Relay Connector, Harness Side	(-)
PCMRC - Pin 2	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to B11.

B11 CHECK FOR AN OPEN VPWR CIRCUIT BETWEEN THE PCM AND THE PCM POWER RELAY

Ignition OFF.

Measure the resistance between:

(+) PCM Power Relay Connector, Harness Side	(-) PCM Connector, Harness Side
VPWR - Pin 5	VPWR - Pin B11, B12

Is the resistance less than 5 ohms?

Yes	No
GO to B12.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

B12 CHECK FOR A SHORT TO VOLTAGE ON THE VPWR CIRCUITS BETWEEN THE PCM AND THE PCM POWER RELAY

Ignition ON, engine OFF.

Measure the voltage between:

(+) PCM Power Relay Connector, Harness Side	(-)
VPWR - Pin 5	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to B13.

B13 CHECK FOR CORRECT PCM OPERATION

Ignition OFF.
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.
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.