C1042 – BMW DTC

BMW DTC C1042 – Brake System Vacuum Pump Control Circuit Low

DTC C1042 meaning on BMW

DTC C1042 on a BMW refers to a fault in the Brake System Vacuum Pump Control Circuit. This diagnostic trouble code indicates that the control circuit for the vacuum pump responsible for assisting the brake system is experiencing a low voltage condition.

BMW DTC C1042 symptoms

Symptoms of DTC C1042 on a BMW may include:

• Illuminated brake warning light on the dashboard
• Decreased brake assist functionality
• Increased pedal effort required to stop the vehicle

BMW DTC C1042 causes

Common causes of DTC C1042 on a BMW include:

• Faulty vacuum pump control module
• Wiring or connector issues in the vacuum pump control circuit
• Low voltage supply to the vacuum pump control module

BMW DTC C1042 seriousness

DTC C1042 should be addressed promptly as it can affect the proper functioning of the brake system. Reduced brake assist can compromise vehicle safety and increase the risk of accidents, especially in emergency braking situations.

How to diagnose DTC C1042 on BMW

To diagnose DTC C1042 on a BMW, a mechanic would typically perform the following steps:

1. Use a diagnostic scanner to retrieve the fault code and related data
2. Inspect the vacuum pump control module and associated wiring for any visible damage
3. Test the voltage supply to the vacuum pump control module
4. Conduct a vacuum pump control module self-test if supported

How to fix DTC C1042 on BMW

To fix DTC C1042 on a BMW, the following steps may be taken:

1. Replace the faulty vacuum pump control module
2. Repair or replace any damaged wiring or connectors in the control circuit
3. Ensure proper voltage supply to the vacuum pump control module
4. Clear the fault code and perform a test drive to verify the repair

How to erase DTC C1042 on BMW

To erase DTC C1042 on a BMW, a diagnostic scanner capable of clearing fault codes is typically used. The mechanic would follow these steps:

1. Connect the diagnostic scanner to the vehicle’s OBD-II port
2. Access the DTC menu and locate the C1042 fault code
3. Select the option to clear the fault code from the system
4. Verify that the fault code has been successfully erased

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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