P2994 critical

Hybrid Transmission High Voltage Interlock

The P2994 code means the vehicle's onboard diagnostic system has detected: Hybrid Transmission High Voltage Interlock. This is a critical severity code.

My Garage →

Keep driving?: No -- stop driving
DIY difficulty: hard
Estimated cost: $800 - $4,000 (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

Hybrid system warning light on
Reduced hybrid system performance
Abnormal electric motor operation
Decreased fuel economy

Probable Causes (Ranked by Likelihood)

Failed high voltage interlock component Very High
Hybrid control module software issue High
High voltage connection corrosion Moderate
Hybrid control module internal fault Low

Step-by-Step Diagnostic Procedure

Scan for hybrid system DTCs with compatible scanner
Inspect high voltage interlock connections and wiring
Measure high voltage isolation resistance
Check hybrid system cooling circuit operation

Frequently Asked Questions

Is this a hybrid-specific code?

Yes, this code is specific to hybrid and electric vehicle transmission systems and requires a technician trained in hybrid vehicle repair.

Is it safe to work on this myself?

No, high voltage hybrid components can be lethal. Only trained and certified hybrid technicians should work on these systems.

Will this affect my fuel economy?

Yes, hybrid transmission issues typically reduce or eliminate the fuel savings that the hybrid system provides, resulting in noticeably higher fuel consumption.