1997 PCED OBDII-Diesel | SECTION 5C: Pinpoint Tests |
AC1 DIAGNOSTIC TROUBLE CODE (DTC) P0107: BARO CIRCUIT LOW INPUT
- DTC P0107 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 BARO sensor/PCM
- short to SIG RTN or PWR GND on BARO sensor circuit
- open VREF circuit
- Key off.
- Disconnect BARO sensor connector.
- Key on/engine off.
- Measure voltage between Pin 2 at harness connector and ground.
Is reading 5v ± 0.5?
| Yes | No |
|---|
| GO to AC2. | SERVICE open in Circuit 351 (BR/W). CLEAR DTCs and RETEST. |
AC2 SIGNAL RETURN CIRCUIT CHECK
- Measure voltage between VREF Pin 2 and signal return Pin 1.
Is voltage reading 5v ± 0.5?
| Yes | No |
|---|
| GO to AC3. | REPAIR open in signal return Circuit 359 (GY/R). CLEAR DTCs and RETEST. |
AC3 BARO SIGNAL WIRE CHECK
- Key off.
- Disconnect PCM. Inspect for damaged, pushed out, or corroded pins. Service as necessary.
- Connect breakout box. Leave PCM disconnected.
- Measure resistance between Pin 84 (49 State except Econoline) or Pin 63 (California and all Econoline) and signal wire Pin 3 at sensor connector.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to AC4. | REPAIR open in Circuit 356 (DB/LG). CLEAR DTCs and RETEST. |
AC4 VREF CIRCUIT CHECK
- Measure resistance between Test Pin 90 and Pin 2 of BARO sensor harness connector.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to AC5. | REPAIR open in VREF Circuit 351 (BR/W). CLEAR DTCs and RETEST. |
AC5 SIG RTN CIRCUIT CHECK
- Measure resistance between Test Pin 91 and Pin 1 and BARO harness connector.
Is resistance less than 5 ohms?
| Yes | No |
|---|
| GO to AC6. | REPAIR open in SIG RTN Circuit 359 (GY/R). CLEAR DTCs and RETEST. |
AC6 GROUNDED SIGNAL WIRE CHECK
- Measure resistance between Pin 84 (49 State except Econoline) or Pin 63 (California and all Econoline) and Pins 25/51/76/77/91 and 103.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| GO to AC7. | REPAIR short to ground in Circuit 356 (DB/LG). CLEAR DTCs and RETEST. |
AC7 CHECK GROUNDED SIGNAL WIRE
- Connect breakout box to PCM.
- Measure resistance between Pin 84 (49 State except Econoline) or Pin 63 (California and all Econoline) and Pins 25/91/51/76/77 and 103.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| REPLACE BARO sensor. CLEAR DTCs and RETEST. | REPLACE PCM. REMOVE breakout box. CLEAR DTCs and RETEST. |
AC8 DIAGNOSTIC TROUBLE CODE (DTC) P0108: BARO CIRCUIT HIGH INPUT
- DTC P0108 indicates barometric pressure out of range high during KOEO Self Test or during continuous diagnostic monitoring.
- Possible causes:
- biased BARO sensor/PCM
- BARO circuit shorted to VREF
- Key on.
- Attempt to induce opposite DTC.
- Disconnect BARO sensor.
- Check DTCs.
Does DTC P0107 appear?
| Yes | No |
|---|
| REPLACE BARO sensor CLEAR DTCs and RETEST. | GO to AC9. |
AC9 CHECK FOR SIGNAL WIRE POWER SHORT
- Key off.
- Disconnect PCM. Inspect for damaged, loose, corroded or pushed out pins.
- Connect breakout box. Leave PCM disconnected.
- Measure resistance between Pin 84 and Pins 55/71/90/97.
Is resistance greater than 10,000 ohms?
| Yes | No |
|---|
| REPLACE PCM. CLEAR DTCs and RETEST. | REPAIR short to power in signal wire Circuit 356 (DB/LG). CLEAR DTCs and RETEST. |
AC: Introduction