Air Conditioning

1996 PCED OBDI

SECTION 18: Diesel Diagnosis — 7.3L DI Engine

AE: Air Conditioning

AE: Introduction

AE1 DTC 1464: A/C ON DURING KOER CYLINDER CONTRIBUTION SELF TEST

Turn A/C-heater control switch to the off position.
Rerun KOER Cylinder Contribution Self Test.

Does DTC 1464 set?

Yes	No
GO to AE2.	Problem may be intermittent. GO to AE4.

AE2 CHECK A/C POWER CIRCUIT FOR SHORT

Key on/engine off.
A/C-heater control switch off.
Disconnect A/C clutch connector.
Measure voltage between A/C clutch connector F-Series Circuit 321 (GY/W), Econoline Circuit 347 (BK/Y) to battery ground.

Is B+ present?

Yes	No
REPAIR short to B+.	GO to AE3.

AE3 CHECK TEST PIN 41 SHORTED TO POWER

Key off.
Disconnect PCM, check for damaged pins, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Key on/engine off.
A/C-heater control switch off.
Measure voltage between Test Pin 41 to ground.

Is B+ present?

Yes	No
REPAIR short to B+.	REPLACE PCM.

AE4 CHECK FOR INTERMITTENT SHORT TO POWER

Key off.
Disconnect PCM, check for damaged pins, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Key on/engine off.
A/C-heater control switch off.
Measure voltage between Test Pin 41 and ground.
Grasp the harness, wiggle and shake harness while working towards the PCM.

Is voltage ever present?

Yes	No
REPLACE short to B+.	No problem found at this time.