1994 PCED OBDI-A | SECTION 18A: Diesel Diagnosis — 7.3L DI Engine |
AC1 DTC 827: BARO CIRCUIT LOW INPUT
DTC 827 indicates barometric pressure out of range low was detected during KOEO Self-Test or during continuous diagnostic monitoring.
Possible causes:
- Open BARO sensor circuit.
- Biased sensor/PCM.
- Short to SIG RTN or PWR GND on BARO sensor circuit.
- Key off.
- Disconnect BARO sensor.
- Disconnect PCM. Check for damaged pins, etc.
- Connect breakout box. Leave PCM disconnected.
- Measure resistance between BARO circuit on sensor harness connector Pin C and Pin 84 on breakout box.
Is resistance less than 5.0 ohms?
| Yes | No |
|---|
| GO to AC2. | SERVICE open in Circuit 356 (DB/LG). RERUN Scan Tool Diagnostic Test. |
AC2 CHECK CIRCUIT 356 (DB/LG) FOR SHORT
- Disconnect BARO sensor.
- Disconnect PCM. Check for damaged pins, etc.
- Connect breakout box. Leave PCM disconnected.
- Measure resistance between Pin 84 and Pins 91/51/76/77 and 103 on breakout box.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| GO to AC3. | SERVICE short circuit in Circuit 356 (DB/LG). RERUN Scan Tool Diagnostic Test. |
AC3 CHECK FOR SHORT ON PIN 84
- Disconnect BARO sensor.
- Connect breakout box and PCM.
- Measure resistance between Pin 84 and Pins 91/51/76/77 and 103.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| REPLACE BARO sensor. RERUN Scan Tool Diagnostic Test. | REPLACE PCM. REMOVE breakout box. RECONNECT BARO sensor. RERUN Scan Tool Diagnostic Test. |
AC4 DTC 828: BARO CIRCUIT HIGH INPUT
DTC 828 indicates barometric pressure out of rough high during KOEO self-test or during continuous diagnostic monitoring.
Possible causes:
- Biased sensor/PCM.
- BARO circuit shorted to VREF.
- Key off.
- Disconnect BARO sensor.
- Disconnect PCM. Check for damaged pins, etc.
- Connect breakout box. Leave PCM disconnected.
- Measure resistance between Pin 84 and Pin 90.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| GO to AC5. | SERVICE short circuit. RERUN Scan Tool Diagnostic Test. |
AC5 CHECK FOR SHORT ON PIN 84
- Disconnect BARO sensor.
- Connect breakout box and PCM.
- Measure resistance between Pin 84 and Pin 90.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| REPLACE BARO sensor. RERUN Scan Tool Diagnostic Test. | REPLACE PCM. REMOVE breakout box. RECONNECT BARO sensor. |
AC: Introduction