P0900 critical

Clutch Actuator Circuit Open

The P0900 code means the vehicle's onboard diagnostic system has detected: Clutch Actuator Circuit Open. This is a critical severity code.

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Keep driving?: No -- stop driving
DIY difficulty: hard
Estimated cost: $300 - $1,500 (parts and labor)

Check Your Fluid First

ANCEL AD310 OBD-II Scanner

Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.

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Read Transmission Codes

LAUNCH CRP123X (Reads All Systems)

Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.

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Common Symptoms

Check Engine Light illuminated
Automated manual transmission will not engage or disengage clutch
Vehicle will not move or stalls immediately
Transmission stuck in neutral

Probable Causes (Ranked by Likelihood)

Faulty clutch actuator motor Very High
Open circuit in clutch actuator wiring High
Disconnected connector at clutch actuator Moderate
TCM output driver failure Low

Step-by-Step Diagnostic Procedure

Check the clutch actuator connector is fully seated
Measure resistance at the clutch actuator motor terminals
Test for continuity in the wiring between the TCM and actuator
Command the clutch actuator with a bidirectional scan tool

Frequently Asked Questions

What is a clutch actuator?

In automated manual transmissions, the clutch actuator is an electric or hydraulic motor that engages and disengages the clutch automatically instead of a driver-operated pedal.

Can I drive at all with P0900?

No, if the clutch actuator circuit is open, the transmission cannot engage the clutch and the vehicle will not move. Have it towed to a repair facility.

Is this code specific to automated manual transmissions?

Yes, P0900 applies to vehicles with automated manual transmissions (AMT) or dual-clutch transmissions (DCT) that use an electrically or hydraulically controlled clutch actuator.