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 P0192: Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage
DTC P0193: Fuel Rail Pressure (FRP) Sensor Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
5 V Reference Voltage | P0107, P0193, P0237, P0642 | P0193 | P0193, P0643, P0236 | --
FRP Sensor Signal | P0192 | P0193 | P0193 | --
Low Reference | -- | P0193 | P0193, P0236, P0643 | --

### Circuit/System Description

The fuel rail pressure (FRP) sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5-volt reference voltage on the 5-volt reference circuit and ground on the reference ground circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

### Conditions for Running the DTC

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

• | The DTCs run continuously within the enabling conditions.

### Conditions for Setting the DTC

#### P0192

The ECM detects that the signal circuit voltage is less than 0.3 volt for more than 4 seconds.

#### P0193

The ECM detects that the signal circuit voltage is more than 4.7 volts for more than 4 seconds.

### Action Taken When the DTC Sets

• | DTCs P0192 and P0193 are Type A DTCs.

• | A message center or an indicator displays Reduced Engine Power.

### Conditions for Clearing the DTC

DTCs P0192 and P0193 are Type A DTCs.

### Diagnostic Aids

A poor connection, improper terminal contact, or improper terminal retention at the C162 multi-way harness connector may set DTC P0193.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Controls Connector End Views

• | Engine Control Module Connector End Views

• | Inline Harness Connector End Views

#### Description and Operation

Fuel System Description

#### 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

• | Scan Tool Data Definitions

• | Scan Tool Data List

• | Scan Tool Output Controls

### Circuit/System Verification

Engine idling, observe the Actual Fuel Rail Pressure parameter with a scan tool. The pressure should be approximately 3.5-5.5 Mpa (508-798 psi). With the engine running at idle, the Actual Fuel Rail Pressure should be close to the Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Actual Fuel Rail Pressure should closely match each other.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the FRP Sensor.
2. Ignition OFF, test for less than 2 ohms of resistance 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 ECM.

3. Ignition ON, test for 4.8-5.2 volts 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 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 ECM.

4. Install a 3A fused jumper wire at the signal circuit terminal 2. Toggle the jumper wire between the low reference circuit terminal 1 and the 5-volt reference circuit terminal 3. Verify the scan tool Actual Fuel Rail Pressure toggles between 0.1 MPa and 20.1 MPa.

⇒ | If the specified parameter does not toggle between the minimum and maximum values, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, replace the FRP sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

• | Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement