P0791
Intermediate Shaft Speed Sensor A Circuit
The TCM detects an electrical fault on the intermediate shaft speed sensor A circuit. Used to compute shift slip and torque converter behavior.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Speed sensor failedCommon
- Wiring open or shortedPossible
Parts involved
- Intermediate Shaft Speed Sensor
- Wiring Harness
P0791 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.