BMW DTC P1C78 – Universal Charger Extension Control Module DC/DC Converter High Voltage Current Sensor Circuit Current Implausible High
DTC P1C78 meaning on BMW
DTC P1C78 on a BMW refers to the Universal Charger Extension Control Module DC/DC Converter High Voltage Current Sensor Circuit Current Implausible High fault. This fault code indicates that the high voltage current sensor circuit in the DC/DC converter control module is detecting a current reading that is higher than expected or outside of the normal operating range.
BMW DTC P1C78 symptoms
Symptoms of the BMW DTC P1C78 fault may include:
- Check Engine Light (MIL) illuminated on the dashboard
- Reduced power or performance
- Vehicle may go into a reduced power or limp mode
- Increased fuel consumption
BMW DTC P1C78 causes
The possible causes of the BMW DTC P1C78 fault include:
- Faulty high voltage current sensor
- Wiring or connection issues in the current sensor circuit
- Internal fault in the DC/DC converter control module
- Software or programming issues
BMW DTC P1C78 seriousness
The DTC P1C78 fault should be addressed promptly as it can affect the performance and drivability of the vehicle. Ignoring this fault may lead to further damage to the vehicle’s electrical system or components.
How to diagnose DTC P1C78 on BMW
To diagnose the DTC P1C78 fault on a BMW, a mechanic would typically perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and any related codes
- Inspect the high voltage current sensor and its wiring for any visible damage or corrosion
- Check the connections to the DC/DC converter control module
- Perform a voltage and resistance test on the current sensor circuit
- Check for any software updates or reprogramming needed for the control module
How to fix DTC P1C78 on BMW
To fix the DTC P1C78 fault on a BMW, the following steps may be taken:
- Replace the faulty high voltage current sensor if necessary
- Repair any damaged wiring or connections in the current sensor circuit
- If the issue lies with the DC/DC converter control module, it may need to be replaced or reprogrammed
- Clear the fault codes and perform a test drive to ensure the issue has been resolved
How to erase DTC P1C78 on BMW
To erase the DTC P1C78 fault code on a BMW, a diagnostic scanner can be used to clear the code from the vehicle’s memory. After the fault code has been cleared, it is recommended to perform a test drive to ensure that the fault does not reoccur.
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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