Intermediate Shaft Speed Sensor Circuit Intermittent
Your transmission's intermediate shaft speed sensor is sending an inconsistent signal to the engine computer, like a flickering light switch that cuts in and out. The ECU can't reliably track transmission speed, which affects shift timing and transmission control.
The ECU monitors voltage signals from the intermediate shaft speed sensor to calculate transmission gear ratios and control shift timing. The sensor should produce a consistent AC or digital signal proportional to shaft rotation speed. Intermittent dropouts in this signal trigger the fault code without a complete circuit failure.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Signal Voltage | Consistent 0.5-4.5V AC or clean digital pulses | Sporadic signal loss, noise, or voltage spikes lasting >2 seconds |
| Signal Continuity | Uninterrupted frequency matching shaft speed | Intermittent dropout events detected by ECU logic |
Code P0794 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0794 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.