P0781 OBD-II Trouble Code: 1-2 Shift Malfunction

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

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0781 code

P0781 is a diagnostic trouble code (DTC) for "1-2 Shift Malfunction". 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 $99.99 . 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 $99.99 $20.0
Toyota $99.99 $20.0
BMW $109.99 $20.0
SCHEDULE P0781 DIAGNOSTIC Get a fair and transparent estimate upfront

P0781 code definition

When your vehicle’s PCM stores a P0781 code, it means that the PCM has identified a problem in the 1-2 shift function.

What the P0781 code means

The automatic transmission in your vehicle uses shift solenoids to move fluid through hydraulic circuits, and make changes in your gear ratio. This affects the way your vehicle shifts, increasing and decreasing speed, optimizing fuel efficiency and maximizing engine performance.

What causes the P0781 code?

When the gear ratio detected is not in sync with the gear ratio needed, then the PCM records a P0781 code, and your Check Engine Light will come on and the code will be stored. Sometimes, though, repeated failures may take place before the Check Engine Light comes on.

Common causes are:

  • Bad shift solenoid

  • Blockages in the transmission fluid lines

  • Failure within the transmission itself

  • Contaminated transmission fluid

  • Bad PCM (this is rare)

What are the symptoms of the P0781 code?

You might actually notice no symptoms at all, until the problem becomes worse. Then, you may experience:

  • Transmission slippage

  • A burning smell due to an overheated transmission

  • Trouble shifting

  • Lower fuel economy

  • Vehicle entering “limp in mode” in order to prevent damage to the transmission Your Check Engine Light will also come on.

How does a mechanic diagnose the P0781 code?

First, your mechanic will attach a digital voltmeter or scanner to your vehicle to see what codes come up. In addition to P0781, codes P0782-P0784 may appear. These codes generally indicate slippage in the transmission.

Now, your mechanic will:

  • Check your transmission fluid to make sure that it is not low or dirty

  • Do a “sniff test” to make sure that the fluid does not give off a burned smell

  • If the fluid smells burned, check the transmission pan for debris

  • If there is debris, flush and replace the fluid and install a new torque converter

  • Check the wiring and harness to see if anything needs to be replaced

Finally, once the diagnostics have been completed, the mechanic will take your car for a test drive to see how it performs, and upon bringing it back, use the scanner again to see if the codes reappear.

A good mechanic will always re-test the vehicle to make sure that any maintenance or repairs have been successful, and will re-test as many times as are necessary in order to ensure that the trouble codes go away and you are driving safely.

Common mistakes when diagnosing the P0781 code

Sometimes, mechanics assume the worst, and blame the PCM or the shift solenoid, when the problem is actually dirty or low fluid. The PCM is hardly ever the issue, and shift solenoids are seldom the problem.

How serious is the P0781 code?

Trouble shifting is hardly ever going to get you killed if you’re just driving around town. If you’re attempting to pass on the Interstate, though, it could be more problematic. You do not have to park your car and call for a tow truck, but you should get this checked out at your earliest convenience. You don’t want any surprises when you’re driving at high speeds.

What repairs can fix the P0781 code?

With a P0781 code, most of the time it is not a matter of repair so much as it is maintenance. Often, topping off or replacing your transmission fluid will correct the problem.

Need help with a P0781 code?

At YourMechanic, we will be pleased to dispatch a qualified mechanic to your home, or your place of work, to do any repairs you might need. Whether the problem is a P0781 code or something else, we are here for you. Call us at 1-800-701-6230, or if you prefer, book an appointment online using our convenient form. We will be happy to provide you with a free quote before we come to see you.

Check Engine Light
trouble codes
P0781

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0781 code.

SCHEDULE P0781 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6529)

Rating Summary
6050
228
53
36
162
6050
228
53
36
162
 at YourMechanic

Kevin

24 years of experience
449 reviews
Kevin
24 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Stone Mountain, Georgia
He is a very knowledgeable Mechanic, and told me where exactly to get my exhaust leak fix. Very honest and thorough Mechanic.
 at YourMechanic

Raymond

27 years of experience
144 reviews
Raymond
27 years of experience
Chevrolet Suburban 1500 - Check Engine Light is on - Apple Valley, California
Raymond is an excellent mechanic, I feel he is very honest and trustworthy. I would recommend him to everyone.
 at YourMechanic

Diana

18 years of experience
46 reviews
Diana
18 years of experience
Ford Escape V6-3.0L - Check Engine Light is on - Union, New Jersey
Fantastic service. Super knowledgeable and courteous. Something you don't get in the brick and mortar shops. A+++++++++
 at YourMechanic

Rusty

23 years of experience
462 reviews
Rusty
23 years of experience
Audi A4 L4-2.0L - Check Engine Light is on - Fort Worth, Texas
Rusty was knowledgeable, friendly, and helpful. He took the time to talk with me about my car and the various repair options I should consider. Highly recommended, and would use him again with high confidence.


More related articles

P0764 OBD-II Trouble Code: Shift Solenoid C Intermittent
P0764 means a faulty shift solenoid and irregular voltage readings; caused by a failed shift solenoid, internal ATF blockages
P3418 OBD-II Trouble Code: Cylinder 3 Deactivation/Intake Valve Control Performance
What What the P3418 code means This code indicates that there is a problem with your intake valve on cylinder number 3. Your vehicle’s control module detects that the measured values from the TP sensor, MAP sensor, and MAF sensor...
Top 7 Reasons Your Check Engine Light is On
While While it’s often assumed that the check engine light (CEL) is an indication of a major mechanical issue, this isn’t always the case. In fact, according to many professional mechanics, a warning light can be caused by a minor...

Related questions

P2006 code is present in the computer.

Hi there. With having the code P2006 present, check the intake wiring to the runner control and see if there is a good connection. Also, the runners in the intake could be clogged and needs cleaned out. A leaking or...

EGR BPT valve & EGR solenoid valve need replacements

Hello there. When codes go away like this, it generally means that the fault has resolved itself or the Check Engine Light has failed in the cluster. If the code is gone this would indicate that there is not a...

Check Engine Light is on, trouble codes P0001 and P0006 are showing.

The fuel shut off valve is a solenoid that is controlled primarily by the shut off relay. The message you are receiving is telling you the circuit has low voltage. This means the solenoid is not energizing the way it...

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