DTC 48 Left Front TCS Pilot Valve Fault: Notes

Left front TCS pilot valve in BPM valve may be commanded to close, isolating master cylinder. Pilot valve circuits receive power through valve relay on BPM valve. Valve relay is engaged at ignition switch in ON position and remains engaged through ignition cycle. Valve solenoid circuits should have battery voltage available at all times.

When ignition switch is turned to RUN position, power is supplied to EBTCM/EBCM. EBTCM/EBCM will complete an internal self-check before providing ground to valve relay. When valve relay is energized, battery voltage is supplied to pilot valves.

DTC 48 sets when expected position of left front TCS pilot valve does not match commanded position from EBTCM/EBCM. Conditions that could cause DTC 48 to set are damage to left front TCS pilot valve, open circuit or short circuit to ground or battery on circuit No. 1657.

NOTE: Test numbers refer to numbers on diagnostic chart.

Damage to circuit No. 886 may result in multiple pilot valve DTCs.
Checks circuit No. 886 for opens or high resistance between EBTCM/EBCM terminals No. 23 and 32.
Checks which branch of circuit No. 886 has an open or high resistance.
Checks integrity of circuits No. 1657 and 886, TCS pilot valve circuitry internal to BPM valve, and TCS pilot valve solenoid coil.
Checks whether a problem found in step 4) is due to an open in circuit No. 886 or 1657, or a faulty BPM valve.
Checks whether problem found in step 4) is caused by open in circuit No. 886 or 1657.
Checks for short to battery voltage in circuit No. 886 using EBTCM/EBCM terminal No. 20 as ground.
Checks for short to battery voltage in circuit No. 1657 using EBTCM/EBCM terminal No. 20 as ground.
Checks for short to ground in circuit No. 886 using EBTCM/EBCM terminal No. 20 as ground.
Checks for short to ground in circuit No. 1657 using EBTCM/EBCM terminal No. 20 as ground.
Checks for connector or wiring problems that could cause intermittents.
Uses Tech 1 to activate TCS pilot valve solenoid and check for correct operation.
Checks whether DTC was set by intermittent conditions or EBTCM fault.