What does it mean?
P1885 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: A/T Drive Pulley Speed Sensor Circuit Malfunction .
Symptoms
- Malfunction indicator lamp on, often with a transmission warning message
- Ratio control becomes erratic: engine rpm rises or drops without matching road speed
- Fixed-ratio limp operation with very poor acceleration
- Jerky launches, surging or an unstable feel under steady throttle
- On some vehicles the speedometer or other displays behave oddly
- The problem may only show up after the transmission warms up
Likely causes
- Failed pulley speed sensor, often heat-related and appearing when the fluid is hot
- Metal debris collected on the sensor tip from internal belt or pulley wear
- Open, short or high resistance in the sensor signal, supply or ground wiring
- Oil-contaminated or corroded connector at the transmission
- Sensor loose in its bore or an incorrect air gap after service
- Damaged tone ring or pulley teeth the sensor reads
- Faulty sensor input in the transmission control module
How to fix it
- Read all transmission codes and record freeze frame data
- Graph drive and driven pulley speeds in live data during a road test and look for dropouts
- Inspect the transmission connector for oil ingress, corrosion and terminal tension
- Measure the sensor supply voltage and ground, then check the signal with a meter or scope
- Remove the sensor and examine the tip — heavy metal debris points to internal wear, not just a sensor fault
- Check the sensor seat, seal and air gap; replace the sensor if the signal drops out with good wiring
- If metal was found on the tip, assess the CVT internally before returning the vehicle to service