P0891 — TCM Power Relay Sense Circuit High

What Does P0891 Mean?

P0891 is a diagnostic trouble code indicating: TCM Power Relay Sense Circuit High. This code relates to the transmission system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P0891

⚠️ Check Engine Light (MIL) illuminated
⚠️ TCM Power Relay Sense reading stuck at maximum value
⚠️ Related system operating erratically or in default mode
⚠️ Harsh or delayed shifting

Common Causes

🔍 Short to voltage in TCM Power Relay Sense wiring harness
🔍 Corroded or water-damaged TCM Power Relay Sense connector
🔍 Faulty TCM Power Relay Sense outputting maximum voltage
🔍 Damaged wiring rubbing against metal components
🔍 ECM/PCM internal fault (rare)

Frequently Asked Questions

What does P0891 mean?

P0891 indicates: TCM Power Relay Sense Circuit High. The vehicle's computer has detected that the TCM Power Relay Sense is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P0891?

Only short distances if absolutely necessary. P0891 affects a critical system and should be diagnosed within a few days to avoid further damage.

How much does it cost to fix P0891?

Repair costs for P0891 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

🔧 Inspect and repair TCM Power Relay Sense wiring for short to voltage
🔧 Clean or replace corroded TCM Power Relay Sense connector
🔧 Replace faulty TCM Power Relay Sense

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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.

P0891: TCM Power Relay Sense Circuit High