Transmission Control System Electrical Malfunction
The P0702 code indicates a general electrical fault in the transmission control system. This means the powertrain control module (PCM) has detected an abnormal voltage or current in the transmission control circuits, often related to the transmission control module (TCM), solenoids, or wiring. This can lead to erratic shifting, limp mode, or transmission failure if not addressed.
01. Most Common Causes
- Faulty transmission control module (TCM)
- Damaged wiring or connectors in the transmission harness
- Blown fuse or relay for the transmission control system
- Internal transmission failure (e.g., solenoid pack)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission stuck in limp mode or fails to shift
- Harsh or delayed shifting
- Transmission slipping or no engagement
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Inspect transmission fluid level and condition.
Step 3: Visually check wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test power and ground circuits at the TCM and solenoids.
Step 5: Use a multimeter or scan tool to check TCM communication and output signals.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with P0702 can cause unpredictable transmission behavior and may lead to complete transmission failure. It's best to have it diagnosed and repaired immediately.
How much does it cost to fix?▼
The cost varies widely depending on the root cause. Simple wiring repairs can cost $150-$300, while replacing a TCM or solenoid pack can range from $400-$1500 or more.