Auxiliary Powertrain Control System

1996 PCED OBDI

SECTION 18: Diesel Diagnosis — 7.3L DI Engine

AP: Auxiliary Powertrain Control System

AP1 VERIFY OPERATION PROCEDURE

Note: For non-speed control vehicles (1995 only), powertrain control module (PCM) may be incorrect. For manual vehicles, processor catch-word must be SOD4 or later. For F-250, F-350, E-350 automatic vehicles, processor catch-word must be TEE5 or later. F-450 automatic must be PRY4 or later. The catch-word tag may be located on the vehicle A-pillar or on the PCM itself.

Verify vehicle has 1995 or later calibration.
Refer to the auxiliary powertrain control manual provided with the system to verify correct operating procedures and entry conditions.

Are entry conditions met and correct calibration installed?

Yes	No
GO to AP2.	CORRECT operating procedure or CORRECT calibration level as required. RETEST system. If system still does not operate, GO to AP2.

AP2 CHECK FOR DTCs

Note: When performing KOER Switch Self 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.

Note: If vehicle is equipped with pre-1995 calibration, you will be unable to perform self test with NGS Tester. Update calibration and retest. If still unable to perform self test, go to AF1.

Verify auxiliary powertrain control system is off before running any NGS Tester self tests.
Using the NGS Tester, run KOEO On-Demand Self Test, KOER Switch Self Test and Retrieve/Clear Continuous DTCs.

Were any DTCs retrieved?

Yes	No
GO to appropriate pinpoint test.	GO to AP3.

AP3 CHECK FOR KEY ON POWER

Disconnect APCM.
Key on/engine off.
Measure for voltage between Pin 2 of the APCM connector vehicle side to ground. Refer to circuit diagram for pin location.

Is battery voltage present?

Yes	No
GO to AP4.	F-Series: REPLACE fuse 18 or REPAIR open in Circuit 296 (W/P). Econoline: REPAIR open in Circuit 16 (R/LG).

AP4 CHECK GROUND CIRCUIT

Key off.
APCM disconnected.
Measure resistance between Circuit 57 (BK), Pin 1 of the APCM connector vehicle side to ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to AP5.	REPAIR open in ground Circuit 57 (BK).

AP5 CHECK FOR OPEN IN (BUS-) CIRCUIT 915 (PK/LB)

Key off.
APCM disconnected.
Measure resistance on Circuit 915 (PK/LB) between the APCM connector vehicle side Pin 3 to the data link connector (DLC) Pin 10.

Is resistance less than 5.0 ohms?

Yes	No
GO to AP6.	REPAIR open in Circuit 915 (PK/LB).

AP6 CHECK FOR OPEN IN (BUS+) CIRCUIT 914 (T/O)

Key off.
APCM disconnected.
Measure resistance on Circuit 914 (T/O) between the APCM connector vehicle side Pin 4 to the DLC Pin 2.

Is resistance less than 5.0 ohms?

Yes	No
REPLACE APCM.	REPAIR open in Circuit 914 (T/O).

AP7 APCM DOESN'T WORK WITH HAZARD FLASHERS

Key off.
Depress service brake pedal.

Does hi-mount stoplight come on?

Yes	No
GO to K1.	GO to AP8.

AP8 CHECK HI-MOUNT STOPLIGHT

Bench test bulb by applying B+ to one side and B- to the other.

Does the bulb illuminate?

Yes	No
GO to AP9.	REPLACE bulb.

AP9 CHECK GROUND CIRCUIT

Measure resistance on Circuit 57 (BK) between the bulb socket and ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to AP10.	REPAIR open in ground Circuit 57 (BK).

AP10 CHECK POWER TO LIGHT

Key off.
Depress service brake pedal.
Using a test light, probe between powering Circuit 569 (DG) for F-Series or 511 (LG) for Econoline and ground.

Does the test light illuminate?

Yes	No
REPAIR loose connection in the bulb socket.	F-Series: REPAIR open in Circuit 569 (DG). Econoline: REPAIR open in Circuit 511 (LG).

AP11 ECONOLINE CUTAWAY ONLY: APCM DOESN'T WORK WITH HAZARD FLASHERS

Key off.
Disconnect brake resistor, located on the left B-pillar.
Measure resistance on Circuit 57 (BK) between resistor connector and ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to AP12.	REPAIR open in Circuit 57 (BK).

AP12 CHECK POWER CIRCUIT TO RESISTOR

Key off.
Depress service brake pedal.
Using a test light, probe between Circuit 511 (LG) of the resistor connector and ground.

Does the test light illuminate?

Yes	No
GO to AP13.	REPAIR open in Circuit 511 (LG).

AP13 CHECK RESISTOR

Measure resistance across the resistor 13A427.

Is resistance 270 ± 10 ohms?

Yes	No
RECONNECT the resistor and GO to K1.	REPLACE the resistor.