Sigma - 88-90

System Type: Nippon 1st Generation 4 channel FWD ABS.

Diagnostic Page References: 1989 or 1990 Service Manual, Vol. 1, Pages 5-8 thru 5-23. Circuit diagrams are in 1989 Vol. 2, pages 8-121 thru 8-125 and 1990 Vol. 2, pages 102-106.

Data Link Connector Location: The diagnostic connector in the Sigma glove box is not used for ABS testing.

Technical Service Bulletins:

1988 Models:
TSB-88-05-004 describes changes in the ABS ECU.

Notes:

1. Use ABS Tester MB991131-02 or an -01 that has been upgraded to -02 specs as evidenced by a silver label inside the ABS Tester box.
2. The Hydraulic Unit Checker MB991131 shown as a special tool in the Sigma V6 Service Manual is not available.
3. The scan tool (MUT-II) cannot be used for ABS electrical diagnosis on Sigma models.
4. If brake fluid is low, the hydraulic unit may be leaking. Evidence of leakage is hydraulic fluid on the outside of the HU housing or at the connections where brake lines enter the HU.