DTC P018B-P018D

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5495419 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 P018B Fuel Pressure Sensor Performance DTC P018C Fuel Pressure Sensor Circuit Low DTC P018D Fuel Pressure Sensor Circuit High Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performanc
5 V Reference	P018C, P1002, P1177, P129B	P018C	P1002, P1177, P129B	P018B
Signal	P018C	P018C, P2635	P018D*	P018B
Low Reference	—	P018D	*	P018B
* Internal control module or component damage may occur if the circuit shorts to B+.

Typical Scan Tool Data Fuel Pressure Sensor

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine = Running Parameter Normal Range: 30 to 743 kPa (4 to 108 PSI)
5 V Reference	0 kPa (0 PSI)	0 kPa (0 PSI)	765 kPa (111 PSI)
Signal	0 kPa (0 PSI)	0 kPa (0 PSI)	765 kPa (111 PSI)

Circuit	Short to Ground	Open	Short to Voltage
Low Reference	—	765 kPa (111 PSI)	—

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.
Signal	The control module input circuit has an internal resistance connected to ground.
Low Reference	Grounded through the control module.

Component	Description
B47 Fuel Pressure Sensor	The sensor measures the pressure in the component: Fuel Line The signal voltage increases when the pressure increases.
K111 Fuel Pump Driver Control Module	The control module K111 supplies the fuel pump with a 3-phase voltage in order to achieve the desired pump speed required for building fuel line pressure.

The control module uses the fuel pressure sensor to constantly adjust the fuel pump’s feed rate so that the ideal pressure is maintained in the low pressure section (between the fuel pump and the high pressure fuel pump) by means of a closed loop control. Conditions for Running the DTC P018B DTC P018C, P018D, P0641, P1029, P102A, P102B, P1255, P129D, P129F, P12A6, = Not set Engine = Running — For greater than 5 s Fuel Pump Enable = On Low Fuel Indicator = Off Frequency the DTC runs = Continuously — After the running conditions are met P018C, P018D Engine = Running Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P018B Fuel Pressure Sensor = Change is less than 30 kPa (4.4 PSI) — For greater than 5 s P018C Fuel Pressure Sensor = Less than 7 kPa (1 PSI) — For greater than 1 s P018D Fuel Pressure Sensor = Greater than 751 kPa (109 PSI) — 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

1. Ignition » On / Vehicle » In Service Mode
2. Verify DTC P0641, P165C is not set. ⇒ If any of the DTCs are set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If none of the DTCs are set
3. Verify there are no DTCs set related to the following component/system: K111 Fuel Pump Driver Control Module 5V Reference ⇒ If a related DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If a related DTC is not set
4. Engine » Running
5. Verify the scan tool parameter: Fuel Pressure Sensor = 7 to 751 kPa (1 to 109 PSI) ⇒ If not between 7 and 751 kPa (1 and 109 PSI) Refer to: Circuit/System Testing ⇓ If between 7 and 751 kPa (1 and 109 PSI) Wiggle the harness and connector: B47 Fuel Pressure Sensor Wiggle the harness and connector: K111 Fuel Pump Driver Control Module ⇒ If the value spikes or drops out Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s) ⇓ If the value does not spike or drop out
6. 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 does not set
7. All OK. Circuit/System Testing

Note

It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the electrical connector: B47 Fuel Pressure Sensor
3. Test for less than 10 Ω between the test points: Low Reference circuit terminal 2 & Ground ⇒ If 10 Ω or greater 3.1. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module 3.2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 2 @ Component harness & Terminal 27 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K111 Fuel Pump Driver Control Module ⇓ If less than 10 Ω
4. Ignition » On / Vehicle » In Service Mode
5. Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 1 & Low Reference circuit terminal 2 ⇒ If less than 4.8 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 2 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 5.4. Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 2 @ Component harness & Terminal 12 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K111 Fuel Pump Driver Control Module ⇒ If greater than 5.2 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

Note

Internal control module or component damage may occur if the circuit shorts to B+. 5.4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 2 @ Component 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 4.8 and 5.2 V

6. Verify the scan tool parameter: Fuel Pressure Sensor = Less than 7 kPa (1 PSI) ⇒ If 7 kPa (1 PSI) or greater 6.1. Ignition/Vehicle » Off 6.2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module 6.3. Ignition » On / Vehicle » In Service Mode 6.4. Test for less than 1 V between the test points: Signal circuit terminal 3 @ Component 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 less than 7 kPa (1 PSI)
7. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 3 & 5 V Reference circuit terminal 1
8. Verify the scan tool parameter: Fuel Pressure Sensor = Greater than 751 kPa (109 PSI) ⇒ If 751 kPa (109 PSI) or less 8.1. Ignition/Vehicle » Off & Remove » Jumper wire(s) 8.2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module 8.3. Test for infinite resistance between the test points: Signal circuit terminal 3 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 8.4. Test for less than 2 Ω between the test points: Signal circuit terminal 3 @ Component harness & Terminal 26 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K111 Fuel Pump Driver Control Module ⇓ If greater than 751 kPa (109 PSI)
9. Test or replace the component: B47 Fuel Pressure Sensor Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Fuel Pressure Sensor Replacement — B47 Fuel Pressure Sensor For control module replacement, programming, and setup refer to: Control Module References