DTC P0091 Without RPO CTF
Circuit Description
The pressure control (PC) valve is used to adjust supply pump discharge amount so as to adjust common rail pressure. Discharge amount from the supply pump to the common rail is determined by PC valve current timing.
Conditions for Setting the DTC
Abnormally low driving voltage with PC valve OFF, pump normal mode, battery voltage higher than 10 volts and no crankshaft position (CKP) sensor faults with the ignition ON.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The ECM limits fuel delivery. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
| • | Poor connections at the ECM |
| Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection. |
| • | Damaged harness |
| Inspect the wiring harness for damage, shorts to ground, shorts to battery, and open circuits. If the harness appears to be OK, observe the PC valve display on the scan tool while moving connectors and wiring harnesses related to the PC valve sensor. A change in the PC valve sensor scan tool display will indicate the location of the fault. |
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Does the DTC set with the engine is running? | -- | Go to Step 2 | Go to Diagnostic Aids |
2 |
Does the voltage measure within the specified range? | 10-14 V | Go to Step 8 | Go to Step 3 |
3 |
Important : If DTC P1298 is also present, test for voltage before measuring the resistance.
Does the resistance measure more than the specified value? | 10 M ohms | Go to Step 5 | Go to Step 4 |
4 |
Does the resistance measure less than the specified value? | 10 ohms | Go to Step 15 | Go to Step 5 |
5 | Measure the resistance on the PC valve harness between pin number C5-1 at the ECM and PC valve 1 and pin number 2. Does each resistance measure less than the specified value? | 0.5 ohms | Go to Step 6 | Go to Step 14 |
6 | Measure the resistance from pin number 1 at the PC valve relay and pin number 2 at the PC valve relay. Does the resistance measure more than the specified value? | 10 M ohms | Go to Step 7 | Go to Step 15 |
7 | Measure resistance between pin number 1 at the PC valve 1 connector and pin number 1 at the PC valve relay. Does the resistance measure less than the specified value? | 2 ohms | Go to Step 8 | Go to Step 10 |
8 | Measure the PC valve coil resistance. Does the resistance measure within the specified range? | 0.9-1.3 ohms | Go to Step 9 | Go to Step 11 |
9 |
Does the voltage measure within the specified range? | 10-14 V | Go to Step 13 | Go to Step 12 |
10 | Repair/replace the PC valve harness. Did you complete the action? | -- | Go to Step 17 | -- |
11 | Replace the PC valve. Did you complete the replacement? | -- | Go to Step 17 | -- |
12 | Repair the wiring harness in between the power supply and the PC valve relay. Did you complete the repair? | -- | Go to Step 17 | -- |
13 | Repair the poor connection at the PC valve harness connector. Did you complete the repair? | -- | Go to Step 17 | Go to Step 16 |
14 | Repair or replace the wiring harness between the ECM and the PC valve. Did you complete the action? | -- | Go to Step 17 | -- |
15 | Repair or replace the wiring harness between the PC valve and the PC valve relay. Did you complete the action? | -- | Go to Step 17 | -- |
16 | Replace the ECM. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 | Clear all DTCs. Does the DTC reset? | -- | Go to Step 1 | Go to Step 18 |
18 | Operate the vehicle. Do any other DTCs set? | -- | System OK | |
