Failed pressure control solenoid (both sources). Faulty or damaged wiring, or a corroded or damaged connector (both sources). Low transmission fluid level (RepairPal). Contaminated fluid or a restricted transmission filter (OBD-Codes.com). Defective transmission pump or valve body, or blocked hydraulic passages (OBD-Codes.com). Faulty PCM or TCM (both sources; RepairPal names the TCM, OBD-Codes.com the PCM). The sources differ: OBD-Codes.com lists several hydraulic and mechanical causes (pump, valve body, passages, filter) that RepairPal doesn't, while RepairPal adds low fluid level.

Repair or replace damaged wiring and clean corrosion from connectors. Correct the fluid level, or change the fluid and filter. Replace the defective pressure control solenoid. Flush the transmission to clean blocked passages, or repair or replace a faulty pump or valve body, when diagnosis points there (OBD-Codes.com). Reflash or replace the PCM/TCM only after other causes are ruled out.

P0971🔧 Transmission / Pressure control solenoidsStop and fix promptly

P0971: Pressure Control Solenoid C Control Circuit High (Meaning, Causes, Fixes)

Q: What does P0971 mean?

P0971 means the transmission computer has seen a high-voltage fault in the electrical circuit of pressure control solenoid "C", the solenoid that sets fluid pressure for shifting. Common causes are a failed solenoid, damaged wiring or a corroded connector, low or contaminated fluid, or less often a faulty PCM/TCM. An automatic transmission changes gears with clutches and bands that are applied by fluid pressure at the right place and time. Pressure control solenoids adjust that pressure so the transmission shifts smoothly; OBD-Codes.com says most automatics have at least three of them, called A, B and C, and newer transmissions with more gears have more. The powertrain control module (PCM), or on some cars a separate transmission control module (TCM), operates the solenoids. OBD-Codes.com says P0971 is set when the PCM detects a high-voltage condition in the pressure control solenoid "C" control circuit, so the solenoid isn't working properly. RepairPal describes it more broadly: the PCM or TCM sets P0971 when it detects an issue with the electrical circuit to or from this solenoid. It is a generic OBD-II code; OBD-Codes.com lists Ford, GMC, Chevrolet, Honda, BMW, Saturn, Land Rover, Acura and Nissan among makes that may use it, and repair steps vary by year, make, model and transmission. Its sibling codes for the same solenoid are P0968 (circuit open), P0969 (range/performance) and P0970 (circuit low).

Q: Can I keep driving with P0971?

Stop and fix promptly. Get it diagnosed soon. RepairPal rates P0971 Urgent, meaning it can cause severe damage or be unsafe. OBD-Codes.com is a little milder: it says the problem usually starts as moderate but can become severe quickly if it isn't fixed, and that a transmission banging into gear can suffer permanent internal damage. If the car shifts hard, slips, or goes into limp mode, drive gently and avoid highway and heavy-traffic driving until it's checked.

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P0971 means

An automatic transmission changes gears with clutches and bands that are applied by fluid pressure at the right place and time. Pressure control solenoids adjust that pressure so the transmission shifts smoothly; OBD-Codes.com says most automatics have at least three of them, called A, B and C, and newer transmissions with more gears have more. The powertrain control module (PCM), or on some cars a separate transmission control module (TCM), operates the solenoids. OBD-Codes.com says P0971 is set when the PCM detects a high-voltage condition in the pressure control solenoid "C" control circuit, so the solenoid isn't working properly. RepairPal describes it more broadly: the PCM or TCM sets P0971 when it detects an issue with the electrical circuit to or from this solenoid. It is a generic OBD-II code; OBD-Codes.com lists Ford, GMC, Chevrolet, Honda, BMW, Saturn, Land Rover, Acura and Nissan among makes that may use it, and repair steps vary by year, make, model and transmission. Its sibling codes for the same solenoid are P0968 (circuit open), P0969 (range/performance) and P0970 (circuit low).

Severity: can I keep driving?

Stop and fix promptly

Get it diagnosed soon. RepairPal rates P0971 Urgent, meaning it can cause severe damage or be unsafe. OBD-Codes.com is a little milder: it says the problem usually starts as moderate but can become severe quickly if it isn't fixed, and that a transmission banging into gear can suffer permanent internal damage. If the car shifts hard, slips, or goes into limp mode, drive gently and avoid highway and heavy-traffic driving until it's checked.

Common symptoms

Check engine light on (OBD-Codes.com)
Increased fuel consumption (both sources)
Transmission doesn't shift properly (RepairPal); OBD-Codes.com lists slipping when shifting and hard shifts that bang into gear
Transmission overheats (OBD-Codes.com)
Possible misfire-like symptoms (OBD-Codes.com)
Transmission put into limp mode by the PCM (OBD-Codes.com)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Failed pressure control solenoid (both sources)
Faulty or damaged wiring, or a corroded or damaged connector (both sources)
Low transmission fluid level (RepairPal)
Contaminated fluid or a restricted transmission filter (OBD-Codes.com)
Defective transmission pump or valve body, or blocked hydraulic passages (OBD-Codes.com)
Faulty PCM or TCM (both sources; RepairPal names the TCM, OBD-Codes.com the PCM)
The sources differ: OBD-Codes.com lists several hydraulic and mechanical causes (pump, valve body, passages, filter) that RepairPal doesn't, while RepairPal adds low fluid level

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Read all stored codes and freeze frame data. Note any other solenoid "C" codes (P0968 to P0970) or transmission codes stored with it.
Check for technical service bulletins (TSBs) for your vehicle, year and transmission. OBD-Codes.com says to do this first because it can point straight to a known fix.
Check the transmission fluid level and look at its condition for contamination. If you can, check records for when the fluid and filter were last changed.
Inspect the wiring and connectors to the pressure control solenoids, the transmission pump and the PCM for damage, loose connections, corrosion and damaged pins.

Typical fixes

Repair or replace damaged wiring and clean corrosion from connectors
Correct the fluid level, or change the fluid and filter
Replace the defective pressure control solenoid
Flush the transmission to clean blocked passages, or repair or replace a faulty pump or valve body, when diagnosis points there (OBD-Codes.com)
Reflash or replace the PCM/TCM only after other causes are ruled out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

The transmission shifts hard, slips, overheats or goes into limp mode
OBD-Codes.com says the advanced steps are vehicle specific and need a digital multimeter plus the technical data for your car, since voltage and fluid pressure specs vary by model and transmission
Continuity checks should be done with the power off; OBD-Codes.com says normal wiring readings are 0 ohms unless the service data says otherwise, and resistance or no continuity means an open or shorted wire
OBD-Codes.com warns it can be misdiagnosed as an engine misfire, a pump problem, an internal transmission problem or a driveline issue

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0971 serious?

It can be. RepairPal rates it Urgent. OBD-Codes.com says it usually starts as moderate but can become severe quickly, and hard shifts that bang into gear can damage the transmission permanently. Get it checked soon.

Can I keep driving with P0971?

Only gently and for short trips until it's diagnosed. If the car is in limp mode, shifts hard or slips, avoid highway driving and get it looked at.

Will a transmission fluid change fix P0971?

Sometimes. Both sources list fluid problems (low fluid per RepairPal, contaminated fluid or a restricted filter per OBD-Codes.com), but P0971 is an electrical circuit code, so the solenoid and its wiring are common causes too. Check fluid and wiring before replacing parts.

What is the difference between P0968, P0969, P0970 and P0971?

All four are for pressure control solenoid "C". P0968 is circuit open, P0969 is range/performance, P0970 is circuit low and P0971 is circuit high, per OBD-Codes.com and RepairPal.

How much does it cost to fix P0971?

Neither source gives a repair cost. It can range from a wiring repair or fluid service to a solenoid, valve body or module replacement, so get a diagnosis and a written estimate first.

Sources

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.