DTC 24

Fig. 006 - Wiring Diagram for Code 24 Vehicle Speed Sensor:

CODE 24, VEHICLE SPEED SENSOR (VSS)

The VSS signal gives the ECM the car speed information. This is accomplished by the ECM supplying battery voltage to CKT 437. The cluster acts as a switch to ground the circuit as the wheels rotate. This switching action occurs approximately 2000 times per mile. The ECM counts the voltage drops in CKT 437 in a given time and converts this information to car speed. This is part of the information used by the ECM to allow the converter clutch to engage and disengage.

Fig. 005 - Chart Code 24 Vehicle Speed Sensor:

1. Checks to see if a VSS signal is getting to the ECM. Voltage should be 4 to 6 volts and varying.
2. Above 10 volts at this point indicates an internal problem with the I.P. cluster, as it is not switching to ground. It must be exchanged or repaired by an authorized repair station.
3. Jumpering harness terminals "B" to "C" at the MAP sensor would normally set Code 33, but the ECM will not set Code 33 if a VSS signal is present. So, at this point, after 10 seconds of engine running in drive, the "CHECK ENGINE" light "off" indicates the VSS circuit is OK.