DTC P1177
Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5500791 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P1177 Fuel Pump Power Control Module Sensor Reference 2 Circuit Diagnostic Fault Information
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performanc |
|---|---|---|---|---|
| 5V Reference | P1177 | — | P1177 | — |
Typical Scan Tool Data Fuel Pump Power Control Module 5V Reference 2
| Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
| Operating Conditions: Ignition = On Parameter Normal Range: Okay | |||
| Fuel Pump Power Control Module 5V Reference 2 Circuit Status | Malfunction | Okay * | Malfunction |
| * Additional DTCs may set ≠ DTCs listed in the DTC Descriptor category “Component related DTC’s will set, excluding DTCs listed in the DTC Descriptor Category” |
Circuit/System Description For an overview of the component/system, refer to: Fuel System Description
| Circuit | Description |
|---|---|
| 5 V Reference | Regulated voltage supplied by the control module. |
| Component | Description | ||
|---|---|---|---|
| K111 Fuel Pump Driver Control Module | The control module contains a microprocessor used to process input data to control outputs. |
Conditions for Running the DTC DTC U0076 = Not set Ignition = On Ignition Voltage = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC 5V Reference Circuit = Less than 4.38 V or Greater than 4.61 V — For greater than 1 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B DTC Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification
- Ignition » On / Vehicle » In Service Mode
- Verify the scan tool parameter: Fuel Pump Power Control Module 5V Reference 2 Circuit Status = Okay ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Verify the DTC does not set. ⇒ If the DTC sets Refer to: Circuit/System Testing ⇓ If the DTC is not set
- All OK. Circuit/System Testing
- Ignition/Vehicle » Off
- Disconnect the electrical connector: B47 Fuel Pressure Sensor
- Ignition » On / Vehicle » In Service Mode
- Verify the scan tool parameter: Fuel Pump Power Control Module 5V Reference 2 Circuit Status = Malfunction ⇒ If not the specified state after disconnecting a component from the circuit Test or replace the component: B47 Fuel Pressure Sensor ⇓ If the specified state with all components disconnected from the circuit
- Test for 4.38 to 4.61 V between the test points: 5 V Reference circuit terminal 1 @ B47 Fuel Pressure Sensor & Ground ⇒ If less than 4.38 V 5.1. Ignition/Vehicle » Off 5.2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module 5.3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 12 @ Control module harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: K20 Engine Control Module ⇒ If greater than 4.61 V 5.1. Ignition/Vehicle » Off 5.2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module 5.3. Ignition » On / Vehicle » In Service Mode 5.4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 12 @ Control module harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇒ If less than 1 V » Replace the component: K111 Fuel Pump Driver Control Module ⇓ If between 4.38 and 4.61 V
- All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Fuel Pressure Sensor Replacement Fuel Filter Replacement For control module replacement, programming, and setup refer to: Control Module References