P1806 Clutch Interlock Switch Circuit Open
The P1806 code indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected an open circuit in the clutch interlock switch circuit. This switch, located on the clutch pedal, prevents the engine from starting unless the clutch pedal is fully depressed, reducing the risk of accidental starts with the transmission in gear. An open circuit means there is a break in electrical continuity between the switch and the control module, preventing the 'clutch depressed' signal from being received.
01. Most Common Causes
- Clutch interlock switch disconnected or with corroded connector
- Open or broken wire between the switch and the control module
- Blown fuse in the interlock circuit
- Faulty or misadjusted clutch switch
- Poor ground in the switch circuit
02. Symptoms You Will Notice
- Engine will not crank or start
- Engine starts without pressing the clutch pedal
03. Step-by-Step Diagnosis
Check for blown fuses related to the clutch interlock circuit
Inspect the clutch switch connector for corrosion or damage
Test continuity between the switch and PCM/TCM
Verify proper adjustment and operation of the clutch switch
Check for poor ground connections in the circuit
1. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may not start, or may start without pressing the clutch, which is a safety concern. It is recommended to have the issue diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $300, depending on whether the switch, wiring, or fuse needs replacement.