2010 Cadillac CTS Sedan AWD V6-3.6L Page 1223
12. If all circuits test normal, replace the brake booster pump relay. If the DTC resets, replace the power brake booster vacuum pump.
Component Testing
1. Ignition OFF, disconnect the vacuum pump relay.
2. Test for 60-180 ohms between terminals 85 and 86.
瀚慖f the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 30 and 85
* 30 and 87
* 30 and 86
* 86 and 87
瀚慖f not the specified value, replace the relay.
4. Install a 30A fused jumper wire between relay terminal 86 and B+. Install a jumper wire between relay terminal 85 and ground.
5. Test for less than 2 ohms between terminals 30 and 87.
瀚慖f greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay
Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Power Brake Booster Auxiliary Pump Replacement (See: Brakes and Traction Control/Power Brake Assist/Hydraulic Brake Booster
Pump/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P258D
DTC P258A-P258D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P258A
- Vacuum Pump Relay Control Circuit
DTC P258B
- Vacuum Pump Performance
DTC P258C
- Vacuum Pump Relay Control Circuit Low Voltage
DTC P258D
- Vacuum Pump Relay Control Circuit High Voltage
Diagnostic Fault Information
