What Does P1801 Mean?
DTC P1801 indicates an open circuit condition in the transmission clutch interlock safety switch circuit. The PCM detects no electrical continuity through the switch circuit, meaning the signal wire is broken or the switch is permanently open. The vehicle may not start or may bypass the safety interlock depending on the failure mode.
Common Causes
30%
Broken wire in the clutch interlock switch circuit
30%
Clutch interlock switch stuck in the open position
20%
Disconnected or backed-out connector pin
10%
Clutch pedal not fully engaging the switch due to wear
10%
PCM connector damage on the switch input pin
Diagnostic Steps
1
Depress the clutch pedal fully and check for a click from the interlock switch; if no click is heard, the switch may be misaligned or stuck.
2
Disconnect the switch and test continuity across its terminals while manually actuating the plunger; an open reading in both positions confirms a failed switch.
3
With the switch disconnected, check for continuity from the switch connector back to the PCM on the signal wire.
4
Inspect the connector for backed-out, bent, or corroded terminals.
5
Check the clutch pedal bracket and switch mounting for looseness that could prevent proper actuation.
Estimated Repair Cost
$25 - $200
Parts + labor, varies by vehicle and location
DTC P1801 indicates an open circuit condition in the transmission clutch interlock safety switch circuit. The PCM detects no electrical continuity through the switch circuit, meaning the signal wire is broken or the switch is permanently open. The vehicle may not start or may bypass the safety inter...
The most common cause of P1801 (Transmission Clutch Interlock Safety Switch Open Circuit) is: Broken wire in the clutch interlock switch circuit
Typical repair costs for P1801 range from $25 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
An open circuit typically prevents the engine from starting, which is a fail-safe behavior. However, if the system is bypassed, the vehicle could start in gear.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1801 to identify the root cause.
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Quick Info
Category
Powertrain
System
Starting System / Transmission
Difficulty
Type
Manufacturer
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