DTC P0557 or P0558

DTC P0557 or P0558

Diagnostic Instructions

DTC Descriptors

Diagnostic Fault Information

Circuit/System Description

The brake servo pressure sensor measures the pressure inside the brake servo. The engine control module (ECM) supplies a regulated 5 V to the sensor on the 5 V reference circuit. The ECM supplies an ground on the low reference circuit. The brake servo pressure sensor provides a signal voltage to the ECM, relative to the pressure changes, on signal circuit. The ECM converts the signal voltage input to a pressure value.

Conditions for Running the DTC

Conditions for Setting the DTC

The ECM detects the brake servo pressure sensor signal circuit is open, shorted to ground, or shorted to a voltage for greater than 1 s.

Action Taken When the DTC Sets

DTCs P0557, and P0558 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0557, and P0558 are Type B DTCs.

Diagnostic Aids

If a shared 5 V reference circuit is shorted to ground or shorted to a voltage, other 5 V reference circuits may be affected.

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 DTCs P0641 is not set.

⇒	If any DTCs are set, refer to:

•	DTC P0641 for LBS

•	DTC P0641 for LSF

2. Engine running, observe the scan tool Brake Servo Pressure Sensor parameter. The reading should be between 0.3-4.8 V.

⇒	If not the specified value, refer to Circuit/System Testing.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B19B Brake Servo Vacuum Sensor.
2. Test for less than 5 Ω between the low reference circuit terminal 2 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.

3. 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.

4. Verify the scan tool Brake Servo Pressure Sensor parameter is greater than 4.8 V.

⇒	If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the Brake Servo Pressure Sensor parameter is less than 0.3 V.

⇒	If greater than the specified range, test the signal circuit for an open circuit or a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

6. If all circuits test normal, replace the B19B Brake Servo Vacuum Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.