For a complete wiring diagram Refer to Section 8W.When Monitored:Ignition on.Set Condition:When the PCM recognizes Brake Switch No.1 is stuck in the high/off position. Two Trip Fault. Three good trips to turn off the MIL.Possible Causes(B15) BRAKE SIGNAL 1 CIRCUIT OPEN(B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO GROUND(Z914) GROUND CIRCUIT OPENSTOP LAMP SWITCHPCMAlways perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).1. ACTIVE DTCStart the engine.Allow the engine to reach normal operating temperature.With a scan tool, select View DTCs.It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.Is the DTC Active or Pending at this time?YesGo To 2NoRefer to the INTERMITTENT CONDITION Diagnostic Procedure.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)2. STOP LAMP SWITCHTurn the ignition off.Disconnect the Stop Lamp Switch harness connector.Measure the resistance between the (Z914) Ground circuit terminal and the (B15) Brake Signal 1 circuit terminal in the Stop Lamp Switch.Apply and release the Stop Lamp Switch while monitoring the ohmmeter.Does the resistance change from below 5.0 ohms to an open circuit?YesGo To 3NoReplace the Stop Lamp Switch.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. (B15) BRAKE SIGNAL 1 CIRCUIT OPEN

Turn the ignition off.Disconnect the C3 PCM harness connector.Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.Measure the resistance of the (B15) Brake Signal 1 circuit from the Stop Lamp Switch harness connector to the appropriate terminal of special tool #8815.Is the resistance below 5.0 ohms?YesGo To 4NoRepair the open in the (B15) Brake Signal 1 circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (B16) Brake Signal 2 circuit in the Stop Lamp Switch harness connector.Is the resistance below 100 ohms?YesRepair the short to ground in the (B16) Brake Signal 2 circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 55. (Z914) GROUND CIRCUIT OPEN

Measure the resistance between the (Z914) Ground circuit and ground in the Stop Lamp Switch harness connector.Is the resistance below 5.0 ohms?YesGo To 6NoRepair the open in the (Z914) Ground circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6. PCMBefore continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.Were there any problems found?YesRepair as necessary.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace and program the Powertrain Control Module per Service Information.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)