1994 PCED OBDI-A | SECTION 18A: Diesel Diagnosis — 7.3L DI Engine |
W1 DIAGNOSTIC TROUBLE CODE (DTC) 549
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| GO to W2. | SERVICE ground short in Circuit 814 (W/BK). RERUN Scan Tool Diagnostic Test. |
W2 CHECK CIRCUIT 361 (R) FOR SHORT
- Key off.
- Measure resistance between Circuit 361 (R) at IDM relay and chassis ground.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| GO to W3. | SERVICE ground short in Circuit 361 (R). RERUN Scan Tool Diagnostic Test. |
W3 CHECK FOR B+ AT IDM RELAY
- Key off.
- Disconnect powertrain control module (PCM). Inspect for damaged or pushed-out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box and connect PCM to breakout box.
- Disconnect IDM relay.
- Key on, engine off.
- Measure voltage on Circuit 361 (R) at IDM relay harness connector.
Is B+ present?
W4 CHECK CIRCUIT 814 (W/BK) FOR OPEN
- Key off.
- Measure resistance between Pin 70 at breakout box and Circuit 814 (W/BK) at the IDM relay harness connector.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to W5. | SERVICE open in Circuit 814 (W/BK). RERUN Scan Tool Diagnostic Test. |
W5 CHECK IDM RELAY OPERATION
- Reconnect IDM relay.
- Key on, engine off.
- Measure voltage at Pin 70.
Is B+ present?
| Yes | No |
|---|
| REPLACE PCM. RERUN Scan Tool Diagnostic Test. | REPLACE IDM relay. RERUN Scan Tool Diagnostic Test. |
W6 CHECK MAXI-8 FUSE FOR OPEN
- Key off.
- Check the MAXI-8 30A fuse for continuity.
Is fuse OK?
| Yes | No |
|---|
| GO to W7. | REPLACE fuse. RERUN Scan Tool Diagnostic Test. |
W7 CHECK CIRCUIT 370 (O/BK) FOR OPEN
- Key off.
- Disconnect IDM relay.
- Measure resistance in Circuit 370 (O/BK) between MAXI-8 30A fuse and IDM relay.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to W8. | SERVICE open in Circuit 370 (O/BK). RERUN Scan Tool Diagnostic Test. |
W8 CHECK CIRCUIT 876 (DG/LG) FOR OPEN
- Key off.
- Disconnect IDM relay.
- Measure resistance in Circuit 876 (DG/LG) between IDM relay and IDM Pin 14.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| REPLACE IDM relay. RERUN Scan Tool Diagnostic Test. | SERVICE open in Circuit 876 (DG/LG). RERUN Scan Tool Diagnostic Test. |
W: Introduction