For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0190 03: Fuel Rail Pressure (FRP) Sensor Circuit Voltage Below Threshold
DTC P0190 07: Fuel Rail Pressure (FRP) Sensor Circuit Voltage Above Threshold
DTC P0191 11: Fuel Rail Pressure (FRP) Sensor Circuit Voltage Above Maximum Threshold
DTC P0191 12: Fuel Rail Pressure (FRP) Sensor Circuit Voltage Below Minimum Threshold

### Circuit/System Description

The fuel rail pressure (FRP) sensor measures the fuel pressure within the fuel rail. The engine control module (ECM) monitors the voltage on the FRP sensor circuits. When the fuel pressure is low, the signal voltage is low. When the fuel pressure is high, the signal voltage is high. The ECM supplies 5 volts to the 5-volt reference circuit and a ground to the low reference circuit. The FRP sensor provides a signal voltage to the ECM, relative to the pressure changes within the fuel rail, on the FRP sensor signal circuit.

### Conditions for Running the DTC

• | The ignition is ON or the engine is running.

• | The DTCs run continuously once the above condition is met.

### Conditions for Setting the DTC

#### P0190 03, P0190 07

The ECM detects that the fuel pressure sensor voltage is less than 0.46 volts, or greater than 0.72 volts for 2 seconds.

#### P0191 12

The ECM detects that the fuel pressure sensor voltage is less than 0.254 volt for 0.5 seconds.

#### P0191 11

The ECM detects that the fuel pressure sensor voltage is greater than 4.7 volt for 0.5 seconds.

### Action Taken When the DTC Sets

• | DTCs P0190 03 and P0190 07 are Type A DTCs.

• | DTCs P0191 11, and P0191 12 are Type B DTCs.

### Conditions for Clearing the DTC

• | DTCs P0190 03 and P0190 07 are Type A DTCs.

• | DTCs P0191 11, and P0191 12 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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 for scan tool information

### Circuit/System Verification

1. Ignition On, observe the DTC information with a scan tool. Verify that DTC P0651 is not set.

⇒ | If DTC P0651 is set, refer to DTC P0641, P0651, or P0697 for further diagnosis.

2. Observe the scan tool Fuel Rail Pressure Sensor voltage parameter. The reading should be between 0.5-4.5 V.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the B47 fuel rail pressure sensor.
2. Test for less than 1 Ω between the low reference circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

3. Install the MAIN fuse. Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal 3 and ground

⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

4. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.8 V.

⇒ | If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 ECM.

5. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.5 V.

⇒ | If greater than the specified range, test the signal circuit for short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

6. If all circuits test normal, test or replace the B47 fuel rail pressure sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Fuel Injection Fuel Rail Assembly Replacement

• | Control Module References for ECM replacement, programming and setup

### Repair Verification

Ignition ON, observe the scan tool DPF soot mass parameter. The parameter should be less than 24 grams.

⇒ | If greater than the specified range, perform a DPF service regeneration. Refer to Exhaust Particulate Filter Cleaning.