14V Power Module Current Sensor Circuit Range/Performance
The P0A87 code indicates a fault in the 14-volt power module current sensor circuit, which monitors the current output of the DC-DC converter that charges the auxiliary battery in hybrid/electric vehicles. The powertrain control module (PCM) detects that the sensor signal is out of the expected range or not performing correctly, often due to a faulty sensor, wiring issues, or a failing DC-DC converter. This can lead to improper battery charging and electrical system malfunctions.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Auxiliary battery not charging properly
- Electrical accessories malfunctioning (e.g., dim lights, weak radio)
- Possible hybrid system warning lights
2. Most Common Causes
- Faulty 14-volt power module current sensor
- Damaged or corroded wiring/connectors in the sensor circuit
- Failing DC-DC converter
- PCM software or hardware issue
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the 14V power module current sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage and resistance per manufacturer specifications.
Step 4: Check the DC-DC converter output voltage and current to ensure proper operation.
Step 5: If all else is fine, update the PCM software or replace the PCM if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can lead to a dead auxiliary battery and loss of electrical functions, potentially stranding you.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and sensor replacement, but could be higher if the DC-DC converter or PCM needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.