description
The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ecu.
The skid control ecu converts these wheel speed signals into a 4-pulse signal and outputs it to the ecm via the combination meter. The ecm determines the vehicle speed based on the frequency of these pulse signals.
Monitor description
The ecm assumes that the vehicle is being driven, when the indicated engine speed is more than 2,300 rpm and 30 seconds have elapsed since the park/neutral position (pnp) switch was turned off. If there is no speed signal from the combination meter, despite these conditions being met, the ecm interprets this as a malfunction in the speed signal circuit. The ecm then illuminates the mil and sets the dtc.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Wiring diagram
Inspection procedure
Hint:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
Hint:
Ok: vehicle speeds displayed on tester and speedometer display are equal.
Standard voltage
Standard voltage
Hint:
The output voltage should fluctuate up and down, similarly to the diagram, when the wheel is turned slowly.
Standard resistance (check for open)
Standard resistance (check for short)
Emission inspection
and maintenance (i/m)
programs
Some states have vehicle emission inspection programs which
include obd (on board diagnostics) checks. The obd system
monitors the operation of the emission control system.
If the malfunction indicator lamp comes on
The obd system determines that a problem exists somewhere in the
emission contr ...
If you have a flat tire
Your vehicle is equipped with a spare tire. The flat tire can be
replaced with the spare tire.
WARNING
â– If you have a flat tire
Do not continue driving with a flat tire.
Driving even a short distance with a flat tire can damage the tire and the
wheel beyond repair, which could result in an accide ...
Random / multiple cylinder misfire detected
Description
When the engine misfires, high concentrations of hydrocarbons (hc) enter the
exhaust gas. Extremely
high hc concentration levels can cause increases in exhaust emission levels.
High concentrations of hc
can also cause increases in the three-way catalytic converter (twc) te ...