DTC 4-1-5 Rear Valve Open Or Short Circuit

DESCRIPTION
If there is an open-circuit in any of the valves or their leads, the signal from the control module will shut off the valve relay.

CONDITIONS FOR DTC
If there is no signal to the valve, the control module detects the fault and posts the DTC.

SYMPTOMS
ABS warning light on, ABS system out of action.

SOURCES OF FAULT
Open-circuit in valve coil or lead, or short-circuit to supply (12 volts). If there is a short-circuit to supply, this will only show up during a self-test at 6 km/h. Short-circuits to 0 volts always show up immediately.

CHECKING VOLTAGE TO VALVES
1. Ignition off.
2. Connect test box between control module and ABS system connector.
3. Ignition on.
4. Connect a voltmeter across test box terminals as follows: Rear wheels, # 20 (0 volts) and # 18.
5. Voltmeter should read approx. 12 volts: Coils and leads are OK. (Short-circuit to + may occur.)

IF READING IS INCORRECT
Go to Checking lead and valve coil resistance.

CHECKING LEAD AND VALVE COIL RESISTANCE
1. Ignition off.
2. Disconnect control module from adapter.
3. Connect an ohmmeter across test box terminals as follows: Rear wheels, # 32 and # 18.
4. Ohmmeter should read approximately 2 ohms: Leads and valve coil OK.

IF ANY READING IS INCORRECT
If ohmmeter reads infinite resistance, this means there is an open-circuit in a lead or valve coil. Go to Checking leads.

CHECKING LEADS
1. Ignition off.
2. Connect an ohmmeter between test box and hydraulic modulator connector terminals as follows: Rear wheels, # 35 and pin 3 (RR).
3. Ohmmeter should read approx. 0 ohms: If reading is correct: Go to Checking valve coil resistance.

IF READING IS INCORRECT
If ohmmeter reads infinite resistance, there is an open-circuit in the lead. Repair open-circuit. Check DTC after repair.

CHECKING VALVE COIL RESISTANCE
1. Ignition off
2. Undo connector from hydraulic modulator.
3. Connect an ohmmeter to the 12-pin female contact on the hydraulic modulator as follows: Pins 4 and 5, rear wheels.
4. If ohmmeter reading is approximately 2 ohms: Resistance in coil is correct.

IF READING IS INCORRECT
If ohmmeter reading is infinite for any coil, there is an open-circuit in that coil. Replace hydraulic modulator. Check DTC after repair.