Auxiliary Transmission Fluid Pump Control Circuit/Open
The P2796 code indicates that the Powertrain Control Module (PCM) has detected an open or short circuit in the control circuit of the auxiliary transmission fluid pump. This pump is typically used in vehicles with start-stop systems to maintain transmission fluid pressure when the engine is off. An open circuit means there is a break in the electrical path, preventing the pump from operating correctly.
01. Most Common Causes
- Faulty auxiliary transmission fluid pump
- Open or shorted wiring in the pump control circuit
- Blown fuse or relay for the auxiliary pump
- Faulty PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission may not shift properly or may go into limp mode
- Start-stop system may be disabled
- Transmission fluid leaks (if pump is damaged)
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the auxiliary transmission fluid pump and its wiring for damage, corrosion, or loose connections.
Step 3: Check the fuse and relay for the auxiliary pump; replace if blown.
Step 4: Test the pump's electrical connector for power and ground using a multimeter.
Step 5: If power and ground are present, test the pump's resistance; if out of spec, replace the pump.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause transmission damage or unexpected behavior, especially if the start-stop system is active.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, but can be higher if the pump needs replacement.