P0891 code meaning
TCM Power Relay Sense Circuit High
Powertrain system Generic code P08xx codes Check engine light
What P0891 means
Some gearboxes draw their power through a relay, such as the transmission control relay in Chrysler's fuse box that feeds the solenoids. P0885 to P0887 cover the coil control of that relay, P0888 to P0892 its sense line, which reads back the switched output and compares it with the command. A dead relay leaves all solenoids without power, so the gearbox drops into its hydraulic emergency gear. P0891 means voltage is present at the relay output although the relay is off: a stuck or welded contact or a back-feed. The module then cannot switch the solenoids off for a safe emergency gear, and it may stay powered after key-off and drain the battery. No maker documents the code.
P0891 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0891
- MIL on
- Battery drains overnight
- Module stays awake after key-off
Common causes of P0891
- Most likelyRelay contact welded or sticking
- PossibleSense or output line shorted to voltage
- Less likelyWrong relay fitted
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Transmission relayRelay wiringFuseTransmission control module
What each part of P0891 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 91 | The exact fault in that area. |
What to do next
- Note P0891 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0891
What does P0891 mean?
P0891 means "TCM Power Relay Sense Circuit High". Some gearboxes draw their power through a relay, such as the transmission control relay in Chrysler's fuse box that feeds the solenoids. It is a generic code, so it means the same on every make.
Is it safe to drive with P0891?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0891 fail an emissions test?
Yes, it can. P0891 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0891 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0891 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.