DTC 24 (VSS) Revised Reference Voltage

File in Section: 6E - Engine Fuel & Emission

Bulletin No.: 41-65-39

Date: January, 1995

SERVICE MANUAL UPDATE

Subject:
Section 6E2 - Upgrade Emissions Only - Revised DTC 24 Vehicle Speed Sensor (VSS) Circuit and Reference Voltage Specification

Models:
1994 Geo Metro with 1.0L Engine (VIN 6 - Upgrade Emissions)

Revised DTC 24 Vehicle Speed Sensor (VSS) Circuit.

Pages affected:
6E2-A2-9
6E2-A2-44
6E2-A2-45
6E2-C1-6

REVISED VEHICLE SPEED SENSOR REFERENCE VOLTAGE





Vehicle Speed Sensor (VSS)

The Vehicle Speed Sensor (VSS) consists of a reed switch built into the speedometer head. The Engine Control Module (ECM) applies 5 VOLTS to the VSS (UPGRADE EMISSIONS*). As the speedometer cable turns, the reed switch closes the circuit to ground four times per revolution of the speedometer cable. As vehicle speed increases, the frequency of ground pulses received by the ECM also increases. Therefore, by calculating the frequency of the ground pulses, the ECM is capable of determining vehicle speed.

*Note:
VSS input voltage on the Standard Emissions is 12 volts.

DTC 24 VSS Circuit Checkout:

Service Manual Update Pages