Output Speed Sensor Circuit Malfunction
The engine computer detected a problem with the output shaft speed (OSS) sensor circuit, which monitors transmission output shaft rotation. This sensor is critical for proper shift timing, torque converter lockup, and speedometer operation.
What You Might Notice
- Speedometer not working or reading erratically
- Delayed or harsh transmission shifts
- Check Engine Light illuminated
- Transmission stuck in limp mode or default gear
- Reduced fuel economy
Most Common Causes
- 1
Faulty Output Shaft Speed Sensor
The OSS sensor has failed internally or is producing an out-of-range signal. This is the most common cause and requires sensor replacement.
- 2
Wiring or Connector Issues
Corroded, loose, or damaged wiring and connectors in the OSS sensor circuit prevent proper signal transmission to the transmission control module.
- 3
Transmission Fluid Temperature Sensor Failure
A failing or disconnected transmission fluid temperature sensor can affect shift logic and trigger this code indirectly.
- 4
Transmission Control Module Malfunction
In rare cases, the transmission control module itself may have failed or lost its ability to properly receive the OSS sensor signal.
How to Diagnose It
- 1
Check Faulty Output Shaft Speed Sensor — The OSS sensor has failed internally or is producing an out-of-range signal. This is the most common cause and requires sensor replacement.
- 2
Check Wiring or Connector Issues — Corroded, loose, or damaged wiring and connectors in the OSS sensor circuit prevent proper signal transmission to the transmission control module.
- 3
Check Transmission Fluid Temperature Sensor Failure — A failing or disconnected transmission fluid temperature sensor can affect shift logic and trigger this code indirectly.
- 4
Check Transmission Control Module Malfunction — In rare cases, the transmission control module itself may have failed or lost its ability to properly receive the OSS sensor signal.
How to Fix It
- 1
Replace Output Shaft Speed Sensor
Locate the OSS sensor on the transmission (typically on the output shaft housing), disconnect the electrical connector, unbolt the sensor, and install a new one. Clear the trouble code after replacement and test drive to verify speedometer and shift quality.
- 2
Inspect and Repair Wiring and Connectors
Check the OSS sensor wiring harness for damage, corrosion, or loose connections. Clean corroded connectors with electrical contact cleaner, repair damaged wiring, and ensure all connections are tight and secure.
- 3
Replace Transmission Fluid Temperature Sensor
If testing shows the transmission fluid temperature sensor is faulty, remove the old sensor from the transmission pan or housing and install a new one. Top up transmission fluid if needed.
- 4
Test Transmission Control Module
If the OSS sensor and wiring are confirmed good, have the transmission control module scanned with advanced diagnostics. If faulty, it may need reprogramming or replacement by a transmission specialist.
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