What Does P1807 Mean?
DTC P1807 indicates the transmission clutch interlock safety switch circuit has a short to battery voltage. This is similar to P1802 but typically applies to a different switch circuit or manufacturer variant. The PCM sees a constant high state, potentially bypassing the starter interlock safety feature.
Common Causes
35%
Signal wire shorted to a power source in the harness
25%
Clutch interlock switch stuck closed or internally shorted
20%
Aftermarket remote start system wired into the clutch switch circuit
10%
Connector damage causing pin-to-pin short with a power wire
10%
PCM input protection circuit fault
Diagnostic Steps
1
Disconnect the clutch interlock switch and check if the code condition clears; if so, the switch is likely stuck closed.
2
With the switch disconnected, measure voltage on the signal wire at the PCM side; battery voltage indicates a harness short.
3
Inspect the full length of the clutch switch wiring for chafing, especially near the steering column and firewall.
4
Check for aftermarket installations that may feed voltage into the switch circuit.
5
Test the switch with an ohmmeter to verify it properly opens when the pedal is released.
Estimated Repair Cost
$40 - $300
Parts + labor, varies by vehicle and location
DTC P1807 indicates the transmission clutch interlock safety switch circuit has a short to battery voltage. This is similar to P1802 but typically applies to a different switch circuit or manufacturer variant. The PCM sees a constant high state, potentially bypassing the starter interlock safety fea...
The most common cause of P1807 (Transmission Clutch Interlock Safety Switch Short Circuit To Battery) is: Signal wire shorted to a power source in the harness
Typical repair costs for P1807 range from $40 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A constant high signal may defeat the clutch interlock, allowing the engine to start in gear and causing unexpected vehicle movement.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1807 to identify the root cause.
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Quick Info
Category
Powertrain
System
Starting System / Transmission
Difficulty
Type
Manufacturer
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