DTC 09

Speed Signal Schematic:

Diagnostic Trouble Code (DTC) 9, Open Or Grounded Speed Signal Circuit:

CIRCUIT DESCRIPTION
A Diagnostic Trouble Code (DTC) 9 is a soft fault. If the speed signal line to the Electronic Brake Control Module (EBCM) drops out and returns, this Diagnostic Trouble Code (DTC) is set in memory. The BRAKE lamp will illuminate when the DTC is set and turn off with the next ignition cycle. Do not replace the EBCM to repair this DTC. An open or grounded speed signal relates to a malfunction in the Vehicle Speed Sensor (VSS) buffer or speed signal circuit (CKT 696). It can be set by a poor connection in the speed signal line.

TEST DESCRIPTION
- Check the voltage in CKT 696.
- Check for an open in CKT 696, a blown VSS buffer fuse, or a malfunctioning VSS buffer.
- Check the voltage applied at the EBCM connector.
- Check for added resistance or an open in CKT 696.

DIAGNOSTIC AIDS
Do not replace the EBCM for this DTC. An EBCM malfunction will not cause this DTC to set. If the BRAKE lamp Is not on, do not ground DLC terminals H to A. Doing so will set a false DTC 9.

This is a soft fault that keeps the BRAKE lamp illuminated until the next ignition cycle. If voltage readings are low or varying, the battery, charging system, or intermittent connections could be the cause. Check these areas before replacing any components.

CAUTION: Do not pierce the electrical connectors, wires, seals, or insulation during testing. Doing so will break the seal and lead to corrosion and failure of the wiring and terminals.