Applicable Systems
OBD-II
Symptoms
Transmission output speed sensor signal fault; TCM cannot determine vehicle speed from transmission; speedometer may not work.
Possible Causes
- Output speed sensor internal failure
- Sensor wiring fault
- Sensor air gap incorrect
Troubleshooting Steps
- Step 1: Check output speed sensor resistance
Resistance within spec - Step 2: Inspect sensor wiring
Wiring intact - Step 3: Check sensor mounting and air gap
Air gap within spec - Step 4: Monitor sensor signal with scanner
Signal present when wheels turning - Step 5: Replace sensor if signal absent
Signal present with new sensor
How to Reset
Clear with OBD-II scanner after sensor replacement.
Common Replacement Parts
- Transmission Output Speed Sensor (OEM spec)
Frequently Asked Questions
- Q: Difference between input and output speed sensors?
Input = turbine speed (before transmission gears). Output = driveshaft speed (after gears). Ratio between them = actual gear ratio. TCM uses this for shift control and slip detection.
Source: SAE J2012 standard DTC list + OBD-II portal
Category: OBD-II