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DTC P0658 or P0659 > < DTC P0630

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DTC P0194

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 Descriptor

DTC P0194 00: Fuel Rail Pressure Sensor Circuit Erratic

Diagnostic Fault Information



Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

5V Reference
P0651 00
P0192 5A, P0192 12
P0651 00
-

Signal
P0192 5A, P0192 12
P0192 5A, P0192 12
P0193 11, P0193 5B
P0194 00

Low Reference
P0192 5A, P0192 12
P0192 5A, P0192 12
-
-
 

Typical Scan Tool Data


Fuel Rail Pressure Sensor


Circuit
Short to Ground
Open
Short to Voltage


Operating Conditions: engine running


Parameter Normal Range: 0.5-4.8 V

5V Reference
5 V
5 V
-

Signal
0 V
5 V
5 V

Low Reference
-
5 V
-
 

Circuit/System Description

The fuel rail pressure sensor measures the fuel pressure within the fuel rail. The engine control module (ECM) monitors the voltage on the fuel rail pressure 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 V to the 5 V reference circuit and a ground to the low reference circuit. The fuel rail pressure sensor provides a signal voltage to the ECM, relative to the pressure changes within the fuel rail, on the fuel rail pressure sensor signal circuit.

Conditions for Running the DTC

•  The engine is running.
•  The DTCs run continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the fuel pressure sensor signal is not plausible.

Action Taken When the DTC Sets

DTCs P0194 is a Type C DTC.

Conditions for Clearing the DTC

DTCs P0194 is a Type C DTC.

Reference Information


Schematic Reference

Engine Controls Schematics


Connector End View Reference

Component Connector End Views


Electrical Information Reference


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 P0192 or P0193 is not set.
⇒ If the DTC is set, refer to DTC P0192 or P0193 .
2. Observe the scan tool Fuel Rail Pressure Sensor voltage parameter. The reading should be between 0.4-4.5 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. Perform the Fuel System Diagnosis .
2. Ignition OFF, disconnect the harness connector at the B47B Fuel Rail Pressure Sensor.
3. Test for less than 5 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 Engine Control Module.
4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
⇒ If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
⇒ If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
5. 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 Engine Control Module.
6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.3 V.
⇒ If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
7. If all circuits test normal, replace the B47B Fuel Rail Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

DTC P0658 or P0659 > < DTC P0630