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Code P0890: Meaning, Causes, and Solutions
What is code P0890?
Code P0890 is a generic powertrain diagnostic code applicable to many OBD-II vehicles (1996 and newer), including brands like Hyundai, Kia, Jeep, Dodge, Ford, Chrysler, and many others. Although generic, repair procedures may vary depending on the manufacturer and powertrain configuration.
This code indicates that the Powertrain Control Module (PCM) has detected low voltage in the Transmission Control Module (TCM) power relay control circuit.
Some vehicles integrate the TCM into the PCM, while others have a separate TCM. When a P0890 is stored, it is common for other codes related to the PCM or TCM to also be present.
The CAN communication network transmits data between these modules and other vehicle controllers, including those managing the transmission, traction system, anti-lock braking system (ABS), and electronic stability. This code often appears alongside codes related to mechanical or electronic issues in the traction system.
Symptoms of Code P0890
A vehicle with this code may experience:
✔️ Deactivation of electronic traction control
✔️ Erratic or harsh shifting
✔️ Gear shifting problems (transmission stuck in gear)
✔️ Deactivation of the ABS
✔️ Other associated codes
Possible Causes of Code P0890
🔧 Faulty power relay or blown fuse
🔧 Vehicle speed sensor failure
🔧 Problems in the CAN network (open or shorted circuits)
🔧 Transmission mechanical failure
🔧 Faulty TCM or PCM or programming error
Severity of Code P0890
If this code is stored, the transmission may operate abnormally, causing harsh shifting or becoming stuck in a specific gear. It is recommended to diagnose and repair the problem promptly to avoid more serious damage.
How to Fix Code P0890?
1. Preliminary Checks
✅ Search for Technical Service Bulletins (TSBs) corresponding to your vehicle (year, make, model, and engine).
✅ Use an OBD-II scanner to retrieve stored codes and freeze frame data. Note this information before clearing the codes.
✅ Clear the codes and test drive the vehicle.
- If the code returns immediately, continue diagnostics.
- If the PCM enters a readiness mode without restoring the code, the problem may be intermittent and require further monitoring.
2. Electrical Component Checks
✅ Check the TCM power fuses and relays. Replace any blown fuses or faulty relays.
✅ Inspect the CAN network wiring and connectors for damaged wires, short circuits, or loose connections.
✅ Test the TCM input voltage with a digital multimeter (DVOM) to detect any anomalies.
3. Sensor and Transmission Module Testing
✅ Measure the voltage of the transmission speed sensor and compare it to the manufacturer’s reference values.
✅ If the problem persists, it may be necessary to reprogram or replace the TCM or PCM.
Codes Associated with P0890
🔎 P0865: Communication problem between PCM and TCM
🔎 Other codes related to traction systems, transmission, or CAN network