Test Procedure

B1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Is DTC P0562, P0685, P068A, P2531, P2533 or P2535 present?

Yes	No
For DTC P0562, GO to B8. For DTCs P0685 or P068A, GO to B9. For DTCs P2531 and P2533, GO to B2. For DTC P2535, GO to B6.	GO to B8.

B2 CHECK THE KEYST PIDS

Access the PCM and monitor the KEYST PID.
Access the GEM/SJB and monitor the IGN_SW PID.
Key ON, engine OFF.

Do both PIDs indicate RUN?

Yes	No
GO to B5.	GO to B3.

B3 CHECK THE IGNITION SWITCH AND HARNESS FOR AN OPEN

PCM connector disconnected.
SJB-A connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
ISP-R - Pin B42	Ground

Measure the voltage between:

(+) SJB-A Connector, Harness Side	(-)
ISP-R - Pin 3	Ground

Are the voltages greater than 10 V?

Yes	No
GO to B4.	CHECK for a damaged ignition switch. REFER to SYSTEM WIRING DIAGRAMS Cell 149 Component Testing. If the ignition switch is OK, REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

B4 CHECK THE ISP-R CIRCUIT FOR A SHORT TO GROUND

Key in OFF position.
Ignition Switch connector disconnected.
Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
ISP-R - Pin B42	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
CHECK the ignition switch for a short to ground. If the ignition switch is OK and DTC P2531 is present, GO to B5. If the ignition switch is OK and DTC P2533 is present, GO to B9.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

B5 CHECK THE PCMRC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Key in OFF position.
PCM Power Relay connector disconnected.
Measure the resistance between:

(+) PCM Connector, Harness Side	(-)
PCMRC - Pin B38	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to B15.	REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

B6 DTC P2535: CHECK FOR CORRECT KEY OPERATION

Key ON, engine OFF.

Does the engine start with the key in ON position?

Yes	No
GO to B7.	GO to B15.

B7 CHECK THE ISP-R/S CIRCUIT FOR A SHORT TO VOLTAGE

Key in OFF position.
PCM connector disconnected.
Key ON, engine OFF.
Measure the voltage between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
ISP-R/S - Pin B39	Negative terminal

Is the voltage less than 1 V?

Yes	No
GO to B16.	CHECK for a damaged ignition switch. REFER to SYSTEM WIRING DIAGRAMS Cell 149 Component Testing. If the ignition switch is OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

B8 CHECK THE B+ VOLTAGE TO PCM POWER RELAY

Key in OFF position.
PCM Power Relay connector disconnected.
Key ON, engine OFF.
Measure the voltage between:

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

Is the voltage greater than 10 V?

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

B9 DTCS P0685 AND P068A: CHECK THE PCMRC CIRCUIT FOR AN OPEN IN THE HARNESS

Key in OFF position.
PCM connector disconnected.
Measure the resistance between:

(+) PCM Power Relay Connector, Harness Side	(-) PCM Connector, Harness Side
PCMRC - Pin 2	PCMRC - Pin B38

Is the resistance less than 5 ohms?

Yes	No
GO to B10.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

B10 CHECK THE PCMRC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Key ON, engine OFF.
Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
PCMRC - Pin B38	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.	For DTCs P0685 or P068A, GO to B15. For DTC P2533, GO to B16. For all others, GO to B11.

B11 CHECK THE ISP-R VOLTAGE AT THE PCM HARNESS CONNECTOR

Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
ISP-R - Pin B42	Ground

Is the voltage greater than 10 V?

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

B12 CHECK THE ISP-R CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Key in OFF position.
Measure the voltage between:

(+) PCM Connector, Harness Side	(-)
ISP-R - Pin B42	Ground

Is any voltage present?

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

B13 CHECK THE INJPWRM CIRCUIT FOR AN OPEN IN THE HARNESS

Fuel Injector connector disconnected.
Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Fuel Injector Connector, Harness Side
INJPWRM - Pin B21	IGN START/RUN - Pin 2

Is the resistance less than 5 ohms?

Yes	No
GO to B14.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

B14 CHECK FOR AN OPEN VPWR CIRCUIT BETWEEN THE PCM AND THE PCM POWER RELAY

Measure the resistance between:

(+) PCM Power Relay Connector, Harness Side	(-) PCM Connector, Harness Side
VPWR - Pin 5	VPWR - Pin B67, B68

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new PCM Power relay. CLEAR the DTCs. REPEAT the self-test.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

B15 CHECK THE ISP-R AND ISP-R/S CIRCUITS FOR INTERMITTENT CONCERNS

Key in OFF position.
PCM connector connected.
Key ON, engine OFF.
Access the PCM and monitor the KEYST PID.
Access the GEM/SJB and monitor the IGN_SW PID.
Turn the key to the ON and START positions, while observing the PIDs.
Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.

Is a concern present during the wiggle test?

Yes	No
REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.	GO to PINPOINT TEST Z .

B16 CHECK FOR CORRECT PCM OPERATION

Key in OFF position.
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.