Circuit Description
An ignition voltage is supplied to the high pressure lock-off (HPL) solenoid through the HPL Relay. The powertrain control module (PCM) controls the HPL Relay by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the controlled component. The PCM monitors the status of the driver. If the PCM detects an incorrect voltage for the commanded state of the driver, DTC P0005 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC.
DTC P0005 High Pressure Fuel Shutoff Relay Control Circuit
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The control module detects that the commanded state of the driver and the actual state of the control circuit do not match. |
| • | The above condition exists for at least 1 seconds. |
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 control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests if the concern is active. You should hear a clicking sound when the HPL Relay is commanded ON and OFF. Repeat the commands as necessary.
-
This step verifies that the control module is providing ground to the HPL Relay.
-
This step tests if a ground is constantly being applied to the HPL Relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
Does the HPL Relay respond to the commanded state? | Go to Step 3 | Go to Step 4 | |
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 6 | |
Does the test lamp remain illuminated with each command? | Go to Step 8 | Go to Step 7 | |
7 | Test the control circuit of the HPL Relay for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
8 | Test the control circuit of the HPL Relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
9 | Inspect for poor connections at the HPL Relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the G/H Van Service Manual. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the G/H Van Service Manual. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
11 | Repair the open or short to ground in the ignition voltage circuit. Refer to Wiring Repairs in Wiring Systems in the G/H Van Service Manual. Did you complete the repair? | Go to Step 14 | -- |
12 | Replace the HPL Relay. Did you complete the replacement? | Go to Step 14 | -- |
13 | Replace the powertrain control module (PCM). Refer to Powertrain Control Module Replacement in Engine Controls in the G/H Van Service Manual. Did you complete the replacement? | Go to Step 14 | -- |
14 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 |
15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
