P0793 OBD-II Trouble Code: Intermediate Shaft Speed Sensor Circuit No signal

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0793 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0793 code

P0793 is a diagnostic trouble code (DTC) for "Intermediate Shaft Speed Sensor Circuit No signal". 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 $69.99. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 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$69.99$20.00
Toyota$69.99$20.00
BMW$69.99$20.00
SCHEDULE P0793 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0793 code definition

An incorrect signal to the Powertrain Control Module (PCM) from the transmission intermediate shaft speed sensor circuit causes the storage of a P0793 trouble code and the Check Engine Light to illuminate. This in turn causes the transmission to fail to provide a proper shift strategy, leading to problems with shifting into gear while driving. Associated codes that are sometimes stored with a P0793 trouble code include P0791, P0792, and P0794.

What the P0793 code means

When shifting gears, the transmission shaft speed increases gradually until the shift point is reached and shifting into the next gear. When the speed is erratic or fails to increase as it should, a P0793 trouble code is stored to the PCM. While the Check Engine Lights illuminates immediately upon storing this code in many models of vehicles, some models might require multiple failure cycles before the indicator lamp comes on.

What causes the P0793 code?

A defective intermediate shaft speed sensor, or either the output or input speed sensor, is usually the cause of a P0793 trouble code. In addition to these causes, damaged or shorted wiring or connectors can also cause the storage of this code. Some additional causes of a P0793 trouble code includes faulty shift solenoids, dirty transmission fluid, faulty engine drivability sensors, a defective valve body, and, while rare, PCM failure.

What are the symptoms of the P0793 code?

Symptoms of a P0793 trouble code commonly include problems with shifting, a wildly fluctuating speedometer, and a decrease in the fuel mileage of the vehicle. In addition, the speedometer can fail altogether, the vehicle might stall when stopping, and the engine could misfire or hesitate while in operation. When diagnosing this code, the mechanic should look for an accompanying input speed sensor code stored on the PCM.

How does a mechanic diagnose the P0793 code?

Diagnosing a P0793 trouble code requires a mechanic to have an advanced scanner on hand, in addition to a digital volt/ohmmeter, a manufacturer's wiring diagram, and an oscilloscope.

  • To begin, the mechanic needs to examine all wiring, connectors, and components. The mechanic is looking for any damage, corroded, or shorts while performing this inspection.

  • The mechanic should also connect the advanced scanner to the diagnostic connection and download any stored trouble codes and the freeze frame data. This can help the mechanic with his diagnosis, especially when trying to determine if the problem is an intermittent condition or not.

  • If the code returns upon clearing, check the reference voltage and ground signal coming from the intermediate shaft speed sensor.

  • If both detect as open, check the continuity and resistance of both circuits using the digital volt/ohmmeter. The mechanic should first make sure that any related control modules are disconnected before proceeding. Failure to do so could result in controller damage.

  • Using the manufacturer's wiring diagram and the volt/ohmmeter, the mechanic also needs to test any related circuits, as well as the sensor, for continuity, comparing their findings to the manufacturer's specifications.

  • If all of the system circuits test as good, the mechanic should connect the oscilloscope to the transmission and observe the data coming from the intermediate shaft speed sensor while the vehicle is running.

  • If everything checks out, disconnect the PCM and test it for fault.

  • Clear the code and retest the system to see if the P0793 trouble code comes back.

Common mistakes when diagnosing the P0793 code

One particular mistake made by mechanics when diagnosing a P0793 trouble code is to assume the problem lies with one of the many vehicle speed sensors, with replacement failing to fix the problem and the code returning. Some other mistaken diagnoses of a P0793 trouble code is identifying the problem as an engine misfire, a faulty fuel system, problems with the transmission, and a vehicle speed or driveline malfunction.

How serious is the P0793 code?

In addition to the usual transmission shifting problems associated with this code, a P0793 trouble code can also produce lower fuel economy, engine misfires, and even vehicle stalling. The transmission needs the correct data from the Intermediate Shaft Speed Sensor Circuit in order to function properly, otherwise the vehicle could have trouble determining the proper gear to shift into.

What repairs can fix the P0793 code?

To repair a P0793 trouble code requires a mechanic to take the following action:

Need help with a P0793 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.

P0793
trouble codes
Check Engine Light

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0793 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

4,240

Rating Summary
3,884
174
45
26
111
3,884
174
45
26
111
Kevin

Kevin

21 years of experience
90 reviews
Kevin
21 years of experience
Kevin was methodical, unhurried, and he took the time to explain the details and to answer my questions.
2002 HYUNDAI SONATA - CHECK ENGINE LIGHT IS ON - DULUTH, GEORGIA
Kenneth

Kenneth

17 years of experience
374 reviews
Kenneth
17 years of experience
Kenneth was extremely knowledgeable. He explained the results of my vehicle diagnosis in terms easy to understand.
2003 GMC YUKON - CHECK ENGINE LIGHT IS ON - LOS ANGELES, CALIFORNIA
David

David

13 years of experience
339 reviews
David
13 years of experience
David came out to check out my check engine light and exchange my crank sensor. He did so with no complaints while raining outside. Efficient and highly recommend David is truly one of a kind.
1998 BUICK LESABRE - CHECK ENGINE LIGHT IS ON - SACRAMENTO, CALIFORNIA
Theodore

Theodore

13 years of experience
814 reviews
Theodore
13 years of experience
An outstanding professional who provides a 360 view and transparency in everything he does. I had a really hard engine problem to repair (Lean System). Theodore tried A then B then C....till he identified what caused the misfire of the engine. Based on my previous horrible experiences with some local car repair shops, i can tell you for a fact that he saved me many 00's, if not 000's, of dollars. Highly recommended, will call him again for some other minor issues with a second car we have.
2006 FORD ESCAPE - CHECK ENGINE LIGHT IS ON - SAMMAMISH, WASHINGTON

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...

Related questions

Q: Car starts hard and occasionally stalls out. Smells like gas when running.

Hello. If you have poor connections at the ignition coils then that will cause cylinder misfires. These loose connections can also shorten the life of the ignition coils. The connectors need to be replaced in order to ensure that there...

Q: Malfunction indicator (MIL) keep blinking

The check engine light is blinking most likely due to the engine is misfiring and the computer is warning you the engine catalytic converter may get damaged if you continue to drive it with the problem. You may have excessive...

Q: Engine problems.

Hello. From what you describe it would appear likely that the backfiring and performance issues are a result of the fuel problem. A rich fuel mixture can be caused by a wide variety of issues. A few things I would...

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.

1-800-701-6230 · hi@yourmechanic.com