Diagnostic Procedures
- Inspect ABS (60-amp) fuse and HEGO (10-amp) fuse. If fuses are okay, go to step 5). If ABS fuse is blown, go to next step. If HEGO fuse is blown, go to step 3).
- Disconnect ABS relay. Using DVOM, check resistance between ABS relay harness connector terminal No. 87 (Black/Red wire) and ground. See Fig 1
. If reading is greater than 10K ohms, replace ABS (60-amp) fuse and go to step 4). If reading is less than 10K ohms, repair Black/Red wire and go to step 10).
- Disconnect ABS relay. Disconnect ABCM. Check resistance between ABS relay connector terminal No. 85 (White wire) and ground. If reading is greater than 10K ohms, replace HEGO (10-amp) and go to step 4). If reading is less than 10K ohms, repair White wire and go to step 10).
- Disconnect ABS relay. Turn ignition On. Check resistance between ABS relay harness connector terminal No. 87 (Black/Red wire) and ground, and between terminal No. 85 (White wire) and ground. See Fig 1
. Turn ignition Off. If readings were greater than 10 volts, go to next step. If reading was zero volts, repair Black/Red wire and/or White wire and go to step 10). If reading was 0-10 volts (insufficient voltage to pull in anti-lock relay. Check battery and charging system. See STARTING & CHARGING SYSTEMS article.
- Perform ABS relay component test. See ABS RELAY
under COMPONENT TESTING. If ABS relay is okay, go to next step. If ABS relay is defective, replace ABS relay and go to step 10).
- Install breakout box. Check resistance between breakout box pin No. 4 and ABS relay harness connector No. 86. See Fig 1
. Check resistance between breakout box pins No. 1 and 4. If reading between breakout box and relay connector is less than 5 ohms, and greater than 10K ohms between breakout box pins, go to next step. If readings were not as specified, repair Red/Yellow wire between ABS relay and ABCM, and go to step 10).
- Disconnect HCU connectors C1 and C2. Check resistance between breakout box pin 25 and ABS relay connector terminal No. 30, reading should be less than 5 ohms. Check resistance between breakout box pin 25 and ground (pin 1), reading should be greater than 10K ohms. If readings were as specified, connect ABS relay and HCU connectors, and go to next step. If readings were not as specified, repair Yellow wire between ABS relay and HCU.
- Using a jumper wire, connect breakout box pins No. 1 and 4. Turn ignition On. Using a DVOM, check resistance between specified breakout box pins, see HCU CIRCUIT CHECK table. Turn ignition Off. If readings were as specified, replace ABCM and go to step 10). If readings were not as specified, go to next step.
HCU CIRCUIT CHECK
| Between Pins No. |
Reading |
| 28 & 1 |
Greater Than 10 Volts |
| 29 & 1 |
Greater Than 10 Volts |
| 30 & 1 |
Greater Than 10 Volts |
| 31 & 1 |
Greater Than 10 Volts |
| 36 & 1 |
Greater Than 10 Volts |
| 37 & 1 |
Greater Than 10 Volts |
| 38 & 1 |
Greater Than 10 Volts |
| 39 & 1 |
Greater Than 10 Volts |
- Disconnect HCU connector C1. Turn ignition On. Check voltage between ground and terminals No. 3, 4, 5 and 12 of HCU connector C1. See Fig 3
. Turn ignition Off. If all readings were greater than 10 volts, replace HCU and go to step 10). If reading were not as specified, repair Yellow wire of affected circuit.
- Restore ABS system and connect all components. Clear DTCs. Test drive vehicle. Check for any DTCs. If DTCs exist, see ANTI-LOCK BRAKE CONTROL MODULE (ABCM) DTC DEFINITIONS
table. If DTCs do not exist, repair is complete. If original DTC is retrieved, repeat step 1).
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.