P0738 — TCM Engine Speed Output Circuit Low

What Does P0738 Mean?

P0738 is a diagnostic trouble code indicating: TCM Engine Speed Output Circuit Low. This code relates to the transmission system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P0738

⚠️ Check Engine Light (MIL) illuminated
⚠️ TCM Engine Speed Output reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Harsh or delayed shifting

Common Causes

🔍 Open or broken wire in TCM Engine Speed Output circuit
🔍 Poor ground connection at TCM Engine Speed Output
🔍 Faulty TCM Engine Speed Output with no output signal
🔍 Disconnected or loose TCM Engine Speed Output connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P0738 mean?

P0738 indicates: TCM Engine Speed Output Circuit Low. The vehicle's computer has detected that the TCM Engine Speed Output is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P0738?

Only short distances if absolutely necessary. P0738 affects a critical system and should be diagnosed within a few days to avoid further damage.

How much does it cost to fix P0738?

Repair costs for P0738 typically range from $20 to $500, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Repair broken wire or restore ground in TCM Engine Speed Output circuit
🔧 Clean and secure TCM Engine Speed Output connector and ground points
🔧 Replace failed TCM Engine Speed Output

1
Find your vehicle above
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P0738: TCM Engine Speed Output Circuit Low