1996 PCED OBDI | SECTION 18: Diesel Diagnosis — 7.3L DI Engine |
AS: Output Circuit Check (OCC) Low
AS1 DIAGNOSTIC TROUBLE CODE (DTC) 1661
- DTC 1661 indicates that the output circuit check is low.
- Possible causes:
- Low battery voltage
- Circuit failure
- Faulty powertrain control module (PCM)
- Perform charging system and battery tests.
Is charging system OK?
| Yes | No |
|---|
| GO to
AS2. | REPAIR charging system as required. |
AS2 VREF CIRCUIT CHECK
- Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Disconnect manifold absolute pressure (MAP) sensor connector.
- Measure resistance from Pin 90 to VREF Circuit 351 (BR/W) at the MAP sensor connector.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to AS3. | IDENTIFY VREF circuit fault. GO to Pinpoint Test B1. |
AS3 VPWR CIRCUIT CHECK
- PCM disconnected.
- Key on.
- Measure resistance from Pins 71 and 97 to the positive battery post.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to AS4. | IDENTIFY VPWR circuit failure. GO to Pinpoint Test A1. |
AS4 PCM GROUND CIRCUIT CHECK
- PCM disconnected.
- Key off.
- Measure resistance from Pins 25, 51, 76, 77 and 103 to the negative battery post.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| REPLACE PCM. RETEST system. | REPAIR ground circuit fault. GO to Pinpoint Test A10. |