P0977 OBD-II Trouble Code: Shift Solenoid B Control Circuit High

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0977 code

P0977 is a diagnostic trouble code (DTC) for "Shift Solenoid B Control Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0977 DIAGNOSTIC Get a fair and transparent estimate upfront

P0977 code definition

The P0977 trouble code notes a problem with the shift solenoid B control circuit.

What the P0977 code means

The P0977 code is a standard OBD trouble code that detects an issue with the shift solenoid valve B control circuit. Shift solenoids are used to help create smooth gear shifts in the automatic transmission. The various shift solenoids control the brakes, bands, and clutches in the transmission, with the B solenoid varying depending on the make and model of the vehicle. The transmission control module (TCM) controls the shift solenoids, and activates and deactivates them as necessary to adjust the gear ratios and facilitate smooth shifting. If the TCM records an abnormal voltage reading from the shift solenoid B control circuit, then that circuit will be disabled, and the powertrain control module (PCM) will note the P0977 code.

What causes the P0977 code?

A few factors can cause the P0977 code to be detected:

What are the symptoms of the P0977 code?

The P0977 trouble code is usually accompanied by the check engine soon Warning Light illuminating on the instrument panel. The vehicle will commonly experience transmission issues, such as harsh shifting, delayed or rough acceleration, and the inability to access certain gears. It is likely that the vehicle will also experience reduced fuel efficiency.

How does a mechanic diagnose the P0977 code?

The P0977 code will be addressed with the aid of a standard OBD-II trouble code scanner. A trained mechanic will use the scanner to look at the freeze frame data and assess the code. Additional trouble codes should also be checked for, and if found, they should be addressed in the order in which the scanner displays them. The trouble codes will then need to be reset, and the vehicle restarted, so the technician can see if the code remains detected. If it does not, then an erroneous trigger or an intermittent error are the most probable culprits.

If the P0977 code returns, then the mechanic will check the transmission fluid. If the fluid is at an insufficient level, then it should be replenished, and the mechanic should thoroughly search for signs of leakage. If the fluid is dirty, it can be flushed out and replaced, but if it is contaminated then there is probably extreme damage to the transmission. This will likely require a replacement, or a full rebuild. Next, the mechanic should visually inspect the electrical components, and replace any wires, connectors, or fuses that are damaged or compromised.

If the issue is not yet found, then a digital volt/ohmmeter can be utilized to help identify the circuit that corresponds to the valve B shift solenoid. After the correct circuit is ascertained, the solenoid, harness, and circuit should all be inspected.

Whenever the technician replaces or repairs a component, the trouble codes should be reset, and the vehicle restarted, so the code can once again be checked for. This helps the technician figure out when the problem is resolved.

Common mistakes when diagnosing the P0977 code

The most frequently made error when diagnosing this code comes from not following the OBD-II diagnosis protocol. It’s very important that technicians always abide by the protocol step by step, as this helps guarantee a diagnosis and repair that is both thorough and efficient.

Shift solenoids are often unnecessarily replaced, when the only issue is something simpler, such as a shorted wire, or dirty transmission fluid.

How serious is the P0977 code?

A vehicle with the P0977 trouble code will still be drivable, though it may experience severe enough transmission problems that it is not practical to drive. If the P0977 code is not addressed, it can cause further damage to the transmission, so it’s important to have the vehicle inspected as soon as the code is noticed.

What repairs can fix the P0977 code?

Repairs for the P0977 trouble code are:

  • Shift solenoid valve B replacement
  • Replacement of the electrical components
  • Replacement or addition of transmission fluid
  • In very rare cases, replacement of the PCM, ECM, or TCM

Additional comments for consideration regarding the P0977 code

The valve B shift solenoid is responsible for different parts of the transmission, depending on the make and model of the vehicle, so the gears that are inaccessible when the P0977 code is detected will differ from car to car.

This code is only applicable for vehicles with automatic transmissions.

Need help with a P0977 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

OBD-II
trouble codes
P0977

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0977 code.

SCHEDULE P0977 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

My 2008 Mini Cooper S has a check engine light on and the code is P0977.
The code P0977 (https://www.yourmechanic.com/article/p0977-obd-ii-trouble-code-shift-solenoid-b-control-circuit-high-by-brady-klopfer) will set if the transmission control module (TCM) records an abnormal voltage reading from a shift solenoid in the transmission. A vehicle with the P0977 trouble code will generally be driveable but due to the potential...

More related articles

P0347 OBD-II Trouble Code: Camshaft Position Sensor A Circuit Low Input (Bank 2)
P0347 P0347 code definition The P0347 Trouble Code refers to an issue with the camshaft position sensor A where the circuit input in bank 2 is too low. What the P0347 code means This is a generic code regarding the...
P0414 OBD-II Trouble Code: Secondary Air Injection System Switching Valve A Circuit Shorted
P0414 code means that there is an issue with the secondary air system due to a failed air pump, a short in the wiring harness, or a faulty hose.
P001A OBD-II Trouble Code: "A" Camshaft Profile Control Circuit/Open
P001A means the camshaft and crankshaft signals have malfunctioned which may cause a poorly running engine, reduced power or a no-start condition.

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com