P024

DTC PO24:

PCM Circuits:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) receives unbuffered speed information from the vehicle speed sensor located in the transaxle assembly. If the PCM detects a vehicle speed of 5 mph or less with a transaxle input speed (turbine speed) of 3000 rpm or greater for 1 second while in any forward gear, Code P024 is set. To avoid any erratic cruise control operation due to an intermittent problem, the cruise control system is disabled for the entire ignition cycle.

TEST CONDITIONS
1. Codes P056 and P091 not set.
2. Transaxle not in PARK or NEUTRAL
3. Transaxle pressure switch indicating not in REVERSE.
4. Transaxle input speed sensor indicating 3000 rpm or greater.

FAILURE CONDITION
Vehicle speed 5 mph or less for 1 second.

ACTION TAKEN
1. PCM turns "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
2. Cruise control is disabled for the entire ignition cycle.
3. Torque converter clutch is disabled.
4. The PCM will substitute a calculated vehicle speed based on the transaxle input speed and the current gear commanded (gear ratio).
5. PCM freezes transaxle in current gear.
6. Torque management is disabled.

NOTES ON FAULT TREE
1. If Code P025 is current, the fault is present and can be diagnosed directly. If P025 is stored as history, use P075 to diagnose because fault is intermittent.
2. The vehicle speed sensor will generate a frequency of greater than 0 Hertz when spun by hand. If it does, the PCM is at fault. If it does not, check wires/sensor for opens and shorts.

NOTE ON INTERMITTENTS
Check for Electromagnetic Interference (EMI) induced on CKTs 400 and 401 by running them along side spark plug wires or high power transmitters (like mobile radios) operating in the vicinity.