What Does P1802 Mean?
DTC P1802 indicates the clutch interlock safety switch circuit has a short to battery voltage. The PCM sees a constant high signal on the switch input regardless of clutch pedal position. This means the PCM cannot distinguish between clutch pressed and released, compromising the safety interlock function.
Common Causes
35%
Wiring short to a power source (chafed wire contacting a hot circuit)
25%
Internally shorted clutch interlock switch stuck closed
20%
Incorrectly wired aftermarket alarm or remote start system
10%
Connector cross-pin contact with an adjacent power wire
10%
PCM internal pull-up circuit fault
Diagnostic Steps
1
Disconnect the clutch interlock switch connector and recheck for the code; if the code clears, the switch is likely shorted internally.
2
With the switch disconnected, check for voltage on the signal wire at the PCM side; voltage present indicates a short to power in the harness.
3
Inspect the wiring harness routing for the switch circuit, looking for chafing against sharp edges or contact with other wiring that carries battery voltage.
4
Check for aftermarket installations (alarm, remote start) that may have spliced into the clutch switch circuit.
5
Test the switch with an ohmmeter to confirm it properly opens and closes with pedal actuation.
Estimated Repair Cost
$40 - $300
Parts + labor, varies by vehicle and location
DTC P1802 indicates the clutch interlock safety switch circuit has a short to battery voltage. The PCM sees a constant high signal on the switch input regardless of clutch pedal position. This means the PCM cannot distinguish between clutch pressed and released, compromising the safety interlock fun...
The most common cause of P1802 (Transmission Clutch Interlock Safety Switch Short Circuit To Battery) is: Wiring short to a power source (chafed wire contacting a hot circuit)
Typical repair costs for P1802 range from $40 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A short to battery may fool the PCM into thinking the clutch is always depressed, allowing the engine to start in gear and causing the vehicle to lurch.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1802 to identify the root cause.
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Quick Info
Category
Powertrain
System
Starting System / Transmission
Difficulty
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