1994 PCED OBDI-A | SECTION 18A: Diesel Diagnosis — 7.3L DI Engine |
S1 CHECK IF GLOW PLUGS ARE CONTINUOUSLY ON DTC 515
Diagnostic Trouble Code (DTC) 515 is set when the PCM detects a fault in the glow plug control circuit.
Possible causes:
- Open/grounded circuit.
- Open fuse (17).
- Worn or damaged glow plug relay.
- Disconnect glow plug relay coil connector (hard shell).
- Turn key to on position.
- Measure voltage at Circuit 16 (R/LG) Pin B to ground.
Is battery positive present?
| Yes | No |
|---|
| GO to S2. | OPEN ignition power circuit. REPAIR short to ground. CHECK fuse (17). |
S2 RELAY COIL RESISTANCE TEST
- Key off.
- Measure resistance of coil at points A and B.
Is resistance within specifications?
| Yes | No |
|---|
| GO to S3. | REPLACE relay. RETEST system. |
S3 GLOW PLUG CIRCUIT SHORT TEST
- Key off.
- Install breakout box with key off.
- Measure resistance from Pin 101 to ground connector A Circuit 1090 (PK/O).
Is the resistance less than 5 ohms?
| Yes | No |
|---|
| FIX short to ground. | GO to S4. |
S4 CHECK CIRCUIT FOR OPEN
- With breakout box installed and PCM disconnected, measure resistance from Pin 101 to glow plug relay harness connector A Circuit 1090 (PK/O).
Is there continuity in this circuit?
| Yes | No |
|---|
| REPLACE PCM. | FIX open. RETEST system. |
S: Introduction