P0904 OBD-II Trouble Code: Gate Select Position Circuit [senses left / right position]

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

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0904 code

P0904 is a diagnostic trouble code (DTC) for "Gate Select Position Circuit [senses left / right position]". 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 P0904 DIAGNOSTIC Get a fair and transparent estimate upfront

P0904 code definition

The P0904 code indicates that the electronic control module, or ECM, has detected a problem with the gate select position censor circuit. This code may also be accompanied by the P0905, P0906, P0907, or P0908 codes.

What the P0904 code means

In most vehicles manufactured today, the TCM and ECM use various sensors to monitor and control the performance of the transmission. One of those sensors is the gate select position sensor, which tells the TCM and ECM what gear position the driver has put the vehicle in. These sensors are also used to monitor brake slippage and to detect clutch application in a manual vehicle. If the ECM is not receiving the correct signal from this sensor, it will register the P0904 code.

What causes the P0904 code?

Most often, bad electrical connections within the circuit are to blame. This may include corroded or damaged wire harnesses, or loose connections. However, a misaligned sensor can also cause this issue. As a last resort, a faulty sensor may be suspected as the cause of the P0904 code.

What are the symptoms of the P0904 code?

Before the P0904 code is detected, the cruise control will usually stop working. In most cases, the Check Engine light will activate within two to three drive cycles after the PCM has detected the issue.

How does a mechanic diagnose the P0904 code?

After an OBD-II scanner detects the P0904 code, a technician should begin by checking the alignment of the sensor. After a transmission repair, it is common for sensors to be misaligned. They may need to be rotated to a neutral baseline in order for the gate select position to be properly detected.

After this repair is performed, the mechanic should clear the code and retest the system. If the code reappears, they should then check all electrical components, looking for any loose, corroded, damaged, or otherwise faulty wiring or connectors. These should be replaced and then the system should be cleared and checked again.

If neither of these repairs gives the correct diagnosis, then the sensor is probably faulty.

Common mistakes when diagnosing the P0904 code

When diagnosing the underlying cause of the P0904 code, the most common mistake is forgetting to disconnect the PCM and the cruise control module when testing circuit resistance. It is also important to clear the code and do a road test after each potential solution is attempted. If the most common repairs do not stop the Check Engine light from reappearing, it can be a sign of an intermittent issue that requires an in-depth inspection and servicing.

How serious is the P0904 code?

If the P0904 code is being detected, a vehicle should be repaired immediately. Without the ability to properly detect the gear, the vehicle can become unsafe to drive, or may become inoperable.

What repairs can fix the P0904 code?

Repairs to address the P0904 code include:

  • Realign any sensors that were not in the correct position.
  • Replace or repair any electrical components that were not operating correctly.
  • Replace a faulty sensor.

Need help with a P0904 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.

Check Engine Light
trouble codes
P0904

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0904 code.

SCHEDULE P0904 DIAGNOSTIC
Get a $20 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.


More related articles

Related questions

Am I safe to continue driving if my steering is off and check engine light is on?
When the steering (https://www.yourmechanic.com/services/brakes-steering-and-suspension-inspection) is concerned, the issues should be taken seriously. Driving without the assistance of power steering is very difficult if the steering fails. If going at high speeds you may not be able to correct in time...
2014 jeep patriot ETC light comes on 1st and flashes then few secs later vehicle stablility comes on....what could it be? Thank y
Hello. Thanks for writing in. The warning lights may be related via computer and it's input sensors. However it is hard to tell without having the vehicle scanned. You will want to start there. Make sure the lights have illuminated,...
My Engine Light has started been displayed since i had my AC repaired. Is it any issue?
The check engine light comes on when the Electronic Control Unit (ECU) has detected a fault and stored a trouble code. The only way to know what is the problem is to scan the ECU with the proper diagnostic equipment....

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