Test 02 - Harness, Relays, Valves

*** THIS ARTICLE INCLUDES CHANGES MADE BY TSB #34 04 90 3105, DATED AUGUST 1990 ***





TEST SEQUENCE
1. Connections needed:
- T-plug (4a) with adapter (A) on Antilock Brake System (ABS) wire harness (1)
- Connecting lead from adapter (A) to cigar lighter, control lamp (red) lights up
2. Switch position on adapter (A) to model "3" and test step 02 (right).





Nominal Values

3. Compare the displayed actual values obtained from the test equipment with the nominal values provided above. If nominal values are not obtained, proceed with the troubleshooting procedures below as needed.

TROUBLESHOOTING

NOTE: Turn "Off" ignition for individual measurements, control unit not connected.

Valve Relay, Coil Resistance
- Check connections at hydraulic unit, Y1 (connector, relay).
- Renew valve relays.
- Measure value display > 80 ohms: Break in wire to valve relay, (from ignition switch, wire 27, lines in the hydraulic unit).
- Measured value display < 48 ohms: Short in wire to valve relay (Pin 1 and 27, lines in the hydraulic unit).

Motor Relay, Coil Resistance
- Check connection at hydraulic unit, Y1 (connector, relay).
- Renew motor relay.
- Measured value display > 58 ohms: Break in wire to motor relay (from Pin 1 to Pin 28, lines in the hydraulic unit). Measured value display < 34 ohms: Short in wire to motor relay (Pin 1 and 28, lines in hydraulic unit).

Valve Resistance
- If the nominal values are not obtained for all four valves: Check wire 32 for a break or a short. Detach connector X31 at the hydraulic unit Y1.

Front Left
- Measure resistance directly at the hydraulic unit Y1 between wire 1 and 4, if the nominal value is not obtained:

Renew hydraulic unit.

- Check wire 2 from the connector X11 control unit to connector X31 hydraulic unit Y1 for a break or a short.

Front Right
- Measure resistance directly at the hydraulic unit Y1 between wire 3 and 4. If nominal value is not obtained:

Renew hydraulic unit.

- Check wire 35 from connector X11 control unit to connector X31 hydraulic unit Y1 for a break or a short.

Rear Left
- Measure resistance directly at the hydraulic unit Y1 between wire 5 and 4. If nominal value is not obtained:

Renew hydraulic unit.

- Check wire 18 from connector X11 control unit to connector X31 hydraulic unit Y1 for a break or a short.

Rear Right
- Measure resistance directly at the hydraulic unit Y1 between wire 7 and 4. If nominal value is not obtained:

Renew hydraulic unit.

- Check wire 19 from connector X11 control unit to connector X31 hydraulic unit Y1 for a break or a short.