P0739 moderate

Transmission Control Module (TCM) Engine Speed Output Circuit High

The P0739 code means the vehicle's onboard diagnostic system has detected: Transmission Control Module (TCM) Engine Speed Output Circuit High. This is a moderate severity code.

My Garage →

Keep driving?: Short distances only
DIY difficulty: hard
Estimated cost: $200 - $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.

Check Price on Amazon

Affiliate link -- we earn a commission at no extra cost to you.

Read Transmission Codes

LAUNCH CRP123X (Reads All Systems)

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

Check Price on Amazon

Affiliate link -- we earn a commission at no extra cost to you.

Common Symptoms

Check Engine Light on
TCM speed output reads high
Harsh or delayed shifting
Transmission may enter limp mode

Probable Causes (Ranked by Likelihood)

Short to power in TCM speed output circuit Very High
Contaminated or low transmission fluid High
Wiring fault in the transmission control circuit Moderate
TCM internal failure Low

Step-by-Step Diagnostic Procedure

Check transmission fluid level and condition; contaminated fluid can cause solenoid failures
Use a scan tool to read transmission control module (tcm) engine speed output circuit high data and compare to specification
Inspect the transmission wiring harness connector for corrosion or damage
Check for related transmission codes that may indicate a broader issue

Frequently Asked Questions

What does P0739 mean?

P0739 indicates a fault in the transmission control module (tcm) engine speed output circuit high. The transmission control module has detected an abnormal condition in this circuit that affects shift quality or transmission pressure control.

Can I drive with this transmission code?

You can drive short distances but the transmission may shift harshly, slip, or enter limp mode (staying in one gear). Avoid heavy towing or aggressive driving. Have the vehicle diagnosed promptly to prevent further damage.

Will changing the transmission fluid help?

A transmission fluid change can help if contaminated fluid is causing solenoid sticking. However, if a solenoid or the valve body has failed, fluid change alone will not resolve the issue.