P0892Generic code

P0892 Code: TCM Power Relay Sense Circuit Intermittent

The P0892 code means the transmission computer power circuit is cutting in and out intermittently. It can send the transmission into limp mode or cause erratic shifting. Because the fault comes and goes, you have to reproduce it by moving the harness and watching live data.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$10 to $400
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0892 code means

The transmission control module (TCM) needs a steady power supply. Some vehicles feed it through a relay that the module itself controls, and others feed it directly from the fuse box. The module monitors its supply voltage constantly.

The module watches the control circuit through its own driver transistor. The P0892 code is set when the circuit shows intermittent dropouts. Before you replace any part, check the fuse, relay, connector and wiring, which are the most common causes.

When the voltage is low or unstable, the transmission shifts erratically or goes into limp mode, and solenoid codes can appear even though the solenoids are good. Check the battery, the alternator, the fuses and the grounds first.

Intermittent faults are found by reproducing them. With the engine running and the scan tool in graphing mode, move the harness section by section, tap the connector gently and, if needed, warm the area with a hair dryer or spray the connector with water. The spot where the reading jumps is where the fault is.

P0892 code symptoms

  • Check engine light or another warning light on.
  • Transmission in limp mode or shifting erratically.
  • Erratic shifts, with gears that come at the wrong time or not at all.
  • Limp mode, usually stuck in a single gear.
  • Several transmission codes stored at the same time.

Likely causes of the P0892 code

  1. Poor contact. Pins that are loose or corroded.
  2. Wire broken inside. The insulation looks intact, but the copper is cracked.
  3. Relay with worn contacts that sometimes fails to close.

How to diagnose the P0892 code step by step

  1. Command the component with the scan tool and check whether it responds.
  2. Check the fuse and the relay. Measure voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. You should see battery voltage with the key on or when the component is commanded.
  4. Measure the resistance of the component and compare it with the manual. Also check its insulation to ground.
  5. Check the control wire. Confirm continuity all the way to the computer and make sure there is no short.
  6. Measure battery voltage and charging voltage.
  7. Measure the voltage drop across the module grounds. It should be under 0.2 volts.

How to fix the P0892 code

  • Repair the connector, the wiring or the power supply feed.
  • Replace the transmission computer power relay or its supply component if it does not respond even with correct power and control signals.
  • Clear the codes and road test the vehicle to verify the repair.

Technical reference data

  • Supply voltage: battery voltage, which is 13.5 to 14.7 volts with the engine running.
  • Voltage drop across a ground under load: below 0.2 volts.
  • Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

Do not give up if the fault will not show up in the shop. Intermittent power problems often appear only when the engine is hot, the road is rough or the weather is wet, so try to recreate those conditions during testing.

P0892 on Chrysler

On many Chrysler vehicles the transmission relay sits in the fuse box in the engine compartment.

P0892 on Ford

On many Ford vehicles the transmission relay sits in the fuse box in the engine compartment.

Frequently asked questions about P0892

Can I drive with a P0892 code?
Yes, but with caution. The transmission may shift erratically or enter limp mode at random, so keep trips short and have it checked soon.
What does the transmission computer power supply do?
The transmission computer needs a steady supply to work. Some vehicles feed it through a relay the module controls, and others feed it directly from the fuse box. The module monitors that supply voltage and sets a code when it looks wrong.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first. They are the usual causes and cost much less than a new component.
How much does it cost to fix P0892?
As a rough guide, between $10 and $400. Most of the cost is the time it takes to find the intermittent spot, and the part itself is often cheap.
What does the P0892 code mean?
The P0892 code is a generic OBD2 code that means the transmission computer power circuit is cutting out intermittently. That points to a poor contact, a hidden wire break or a worn relay.
Will a P0892 code clear itself?
The light may go out after several clean drive cycles, but the fault is still in the circuit. It will come back the next time the contact opens.
What is the most common cause of P0892?
A poor contact at a connector pin. Wires broken inside their insulation and relays with worn contacts follow.

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