Circuit Description
The pressure control valve (PCV) is used to adjust supply pump discharge amount to adjust common rail pressure. Discharge amount from the supply pump to the common rail is determined by PCV current timing.
If the engine control module (ECM) detects a PCV 2 signal voltage that is excessively high, DTC 0248 will be set.
Conditions for Setting the DTC
Abnormally low driving voltage with PCV 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 ECM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected. |
| • | Common rail pressure is limited to 60 MPa (8,702 psi) or less. |
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. |
DTC 0248 can be cleared by using the Clear Info on the scan tool or by using the Diag Clear Switch.
Diagnostic Aids
Inspect for the following conditions:
| • | Poor connection 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 PCV display on the scan tool while moving connectors and wiring harnesses related to the PCV sensor. A change in the PCV sensor scan tool display will indicate the location of the fault. |
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Does DTC 0248, reset while the ignition is ON or the engine is running? | -- | Go to Step 2 | Go to Diagnostic Aids |
2 |
Does each voltage measure within the specified range? | 10-14 V | Go to Step 8 | Go to Step 3 |
3 |
Important: If DTC 0421 is also present, inspect 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 10 | Go to Step 5 |
5 | Measure resistance on the PCV harness between pin number 31, 32 for PCV 2 and pin number 2. Does the resistance measure less than the specified value? | 2 ohms | Go to Step 6 | Go to Step 10 |
6 | Measure the resistance from pin number 1 at the PCV relay and pin number 82 at the ECM . Does the resistance measure more than the specified value? | 10 M ohms | Go to Step 7 | Go to Step 10 |
7 | Measure resistance between pin number 1 at the PCV 2 and pin number 1 at the PCV relay . Does the resistance measure less than the specified value? | 2 ohms | Go to Step 8 | Go to Step 10 |
8 | Measure the PCV 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 PCV harness. Did you complete the action? | -- | Go to Step 15 | -- |
11 | Replace the PCV. Did you complete the replacement? | -- | Go to Step 15 | -- |
12 | Repair the wiring harness in between power supply and PCV relay. Did you complete the repair? | -- | Go to Step 15 | -- |
13 | Repair the poor connection at the PCV harness connector. Did you complete the repair? | -- | Go to Step 15 | Go to Step 14 |
14 | Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 | Clear all DTCs. Does DTC 0248 reset? | -- | Go to Step 1 | System OK |
