P0791 code meaning
Intermediate Shaft Speed Sensor A Circuit
Powertrain system Generic code P07xx codes Check engine light
What P0791 means
The intermediate shaft speed sensor measures a shaft between input and output – a countershaft on Toyota's U760 six-speed, the intermediate shaft behind the overdrive set on Ford's 5R110W. Together with turbine and output speed it lets the module check each gear stage and control clutch slip. Ford uses P0791 as its only intermediate shaft code, for 'no or too little signal': while the vehicle drives under power (turbine at least 1500 rpm, output at least 650 rpm or 15 mph), the sensor reports below 250 rpm for 5 s – in the 2012 and 2020–23 summaries, with MIL. A Toyota bulletin for the U760 (Highlander, Venza, Camry 2009–10) replaces the countershaft sensor for P0791/P0793. GM's 10-speed has two such sensors but uses its own codes. Limp mode and harsh shifts follow.
P0791 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0791
- Check engine light
- Limp mode or fixed gear
- Harsh or delayed shifts
- Follow-up pressure control codes (Toyota)
Common causes of P0791
- Most likelyIntermediate shaft speed sensor faulty
- PossibleConnector or wire at the transmission (oil, corrosion, chafing)
- PossibleReluctor wheel damaged or debris on the sensor
- Less likelyControl module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Intermediate shaft speed sensorSensor wiringTransmission control module
What each part of P0791 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7 | Area: transmission. |
| 91 | The exact fault in that area. |
What to do next
- Note P0791 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0791
What does P0791 mean?
P0791 means "Intermediate Shaft Speed Sensor A Circuit". The intermediate shaft speed sensor measures a shaft between input and output – a countershaft on Toyota's U760 six-speed, the intermediate shaft behind the overdrive set on Ford's 5R110W. It is a generic code, so it means the same on every make.
Is it safe to drive with P0791?
Drive gently and only to a workshop. With P0791 the car can go into limp mode (reduced power) to protect itself.
Will P0791 fail an emissions test?
Yes, it can. P0791 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0791 to fix?
Difficulty: medium. A typical repair takes 1.5 to 3 hours of work. This is a job for a workshop.
Will P0791 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.