Drive Cycle Test

NOTE: This test will provide information on symptom evaluations, symptom repeatability, and repair verification.

Low Speed ABS Stop

If possible, drive on wet road condition and have assistant monitor wheels during ABS stop. Drive at 10 MPH, press brake pedal hard enough to lock all wheels. If one wheel locks consistently and if ABS warning light does not come on, see WHEELS LOCK UP under INTERMITTENT FAILURES. If ABS warning light comes on, go to step 7) . If one wheel does not lock up consistently and ABS warning light does not come on, go to next step.

Check For Unwanted ABS Activity

Drive vehicle at 20 mph. Perform light-to-medium stop. If pump motor turns on and brake pulsations are felt, and if ABS warning light comes on, see ABS MISFIRE, TOO SENSITIVE, ACTIVATES ON NORMAL STOPS under INTERMITTENT FAILURES. If ABS warning light comes on and stays on, go to step 7) . If preceding does not happen and other symptoms are present, go to step 6) . If ABS warning light does not come on, go to next step.

Check For Marginally High Sensor Gap At Idle

Connect scan tester and clear any continuous DTCs. Turn ignition off, then start and idle vehicle. Allow vehicle to creep forward at idle for at least 45 seconds. If ABS warning light comes on, go to step 8) . If light does not come on, go to next step.

Check For Marginally High Sensor Gap

Clear any continuous DTCs. Turn ignition off. Start vehicle and slowly accelerate to 25 MPH, making sure this takes at least 45 seconds. If ABS warning light comes on, go to step 8) . If light does not come on, go to next step.

Determine If Drive Test Is Complete

If customer concern has been addressed and corrected by previous steps, test is complete. If concerns remain, go to INTERMITTENT FAILURES .

Determine Next Diagnostic Step Based On Brake Symptom

Test for lack of sufficient deceleration during braking or if vehicle pulls and pump motor does not come on. If either symptom occurs, go to INTERMITTENT FAILURES . If neither symptom occurs, problem is not in ABS system. Refer to appropriate DISC & DRUM article for diagnosis.

Retrieve DTCs

Connect scan tester and retrieve codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES . If DTC is same as before and proper Pinpoint Test has been completed, go to INTERMITTENT FAILURES . If Pinpoint Test is not complete, return to last step and complete test. If different DTC is retrieved, go to DTC TEST INDEX table. If ABS control module does not respond, go to SYSTEM PRE-CHECK .

Determine Which Sensor Signal Is Incorrect

Retrieve and record continuous DTCs. Is sensor code is obtained, see DTC TEST INDEX table. If no code or no SYSTEM PASS is obtained, see SYSTEM PRE-CHECK .

DTC TEST INDEX

DTC

Circuit Description

Go To Test

None

ABS Light On With System Pass

B1318

ABCM - Low Voltage

B1342

ABCM Failure

⁽¹⁾

C1095

HCU Pump Motor - Circuit Shorted

C1096

HCU Pump Motor - Circuit Open

C1115

ABS Relay Shorted

C1140

Excessive Dump Time Fault

C1145

Right Front Sensor (Static)

C1148/C1234

Right Front Sensor (Dynamic)

C1155

Left Front Sensor (Static)

C1158/C1233

Left Front Sensor (Dynamic)

C1165

Right Rear Sensor (Static)

C1168/C1235

Right Rear Sensor (Dynamic)

C1175

Left Rear Sensor (Static)

C1178/C1236

Left Rear Sensor (Dynamic)

C1184

Excessive ABS Isolation

C1185

Open ABS Relay

C1194/C1196

Left Front Dump Solenoid

C1198/C1200

Left Front Isolation Solenoid

C1210/C1212

Right Front Dump Solenoid

C1214/C1216

Right Front Isolation Solenoid

C1220

ABS Warning Indicator - Shorted

C1222

Wheel Speed Error

C1242/C1244

Left Rear Dump Solenoid

C1246/C1248

Right Rear Dump Solenoid

C1250/C1252

Left Rear Isolation Solenoid

C1254/C1256

Right Rear Isolation Solenoid

None

No Communication With Module

⁽¹⁾	Replace ABCM.