vehicle is moving. All of the Ford trucks we’re going to look at use a per-manent magnet, AC-generating sensor, also called a variable reluctance sen-sor. How the AC VSS Works The permanent magnet AC sensor consists of two basic components: the speed sensor itself and a trigger wheel (figure 1). Trigger wheelis a generic My 1996 850 turbo wagon has a persistent Check Engine light due to a vehicle speed sensor malfunction (P0500). The speedometer works fine which I believe uses the anti-lock braking system for vehicle speed information. Since my wiring harnesses were in bad shape I traced the wires for continuity from the sensor to a multipin connector located Use a Scanner to Determine if the VSS is Reporting any Speed. Plug a good scanner into the OBD II port. You can configure it to report the vehicle’s speed as reported by the VSS. If it says 0 MPH while driving, the VSS has likely caused your Chevy Spark’s speedometer to stop working. The video below shows exactly how to use a scanner to The ECM sends a CAN serial data message to the BCM indicating the vehicle speed. The BCM sends a class 2 message to the IPC indicating the vehicle speed. The speedometer defaults to 0 km/h (0 mph) when any of the following occur: • The EBCM detects a malfunction in the vehicle speed sensor circuit. Took it to Advance Auto Parts for a OBD code read. Got a P0500 - Vehicle Speed Sensor Malfunction. Part # 090-5018 for new sensor from AAP, and more than $150 bucks. I did have AAP worker clear the CEL. It drove fine around town (taking it easy), but I hit the country roads and tried to reproduce the problem. Regardless, a VSS malfunction would normally set P0501 or P0502, not P0505. However, if the VSS signal is interpreted as a vehicle speed of zero then the IAC will attempt to control idle whenever the TPS signal is < 1%. This loss of VSS speed pulse could trigger a P0505 code if you are down shifting with a closed throttle for more than 5 seconds. The speed sensor is held in by one bolt. Unscrew the bolt and pull the speed sensor out of the hole. Clean the filings off the bottom and re-insert. Put bolt back in and see if that clears your problem. On my bike the power from the ecm to the speed sensor also connects to the throttle position and map sensors, so there can be interaction. P0141 Code: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) A typical oxygen sensor has a heater circuit that works to bring the sensor up to operating temperature quickly. Code P0141. indicates a problem with the heater circuit of the bank 1 downstream O2 sensor. P0302 Code: Cylinder 2 Misfire Detected. GJG7i7.