Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is not getting enough power from the transmission control module's relay. It's like when a toy doesn't work because the batteries are too low.
The P0890 code indicates that the Transmission Control Module (TCM) is not receiving the correct voltage from the power relay. This could be due to a low voltage condition or a fault in the relay circuit.
The Transmission Control Module (TCM) relies on a power relay to supply it with the necessary voltage to operate. If the TCM detects that the voltage from this relay is below the expected threshold, it will trigger the P0890 code. This could be due to issues such as a faulty relay, poor electrical connections, or wiring problems.
• Check Engine Light is on
• Transmission may not shift properly
• Vehicle may go into limp mode
• Faulty TCM power relay
• Poor electrical connections
• Damaged wiring or connectors
TCM: Transmission Control Module
Relay: An electrical switch that opens and closes under the control of another electrical circuit.
• Check for any other related trouble codes.
• Inspect the TCM power relay and its connections.
• Test the voltage at the TCM power relay circuit.
• Replace the faulty TCM power relay.
• Repair or replace damaged wiring or connectors.
• Ensure all electrical connections are secure and clean.
• Multimeter
• OBD-II scanner
• Basic hand tools
$100 - $300
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain electrical connections.
• Replace relays at recommended intervals.
• Ensure battery and charging system are in good condition.
Electrical Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Avoid driving the vehicle extensively until repaired.
Check with the vehicle manufacturer for warranty coverage on electrical components.
This code has been associated with issues in vehicles with aging electrical systems or those exposed to harsh conditions.
Moderate – It is advisable to address this issue soon to avoid potential transmission problems.
Driving with a malfunctioning transmission control system can lead to unsafe driving conditions.
• Engine running
• Transmission in normal operating mode
The TCM power relay is typically located in the vehicle's fuse box or relay panel, often under the hood.
Q: Can I drive with a P0890 code?
A: It's not recommended to drive extensively with this code, as it may lead to transmission issues.
Q: How can I reset the P0890 code?
A: The code can be reset with an OBD-II scanner, but it's important to fix the underlying issue first.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.