Mazda MX-3 silhouetteMX-3

ANTI-LOCK BRAKE SYSTEM

P-66prose procedure

Check ABS relay harness (fail-safe relay)

  1. 1
    Turn the ignition switch OFF and disconnect the ABS control module connector (18 pin).
    ABS control module 18-pin connector terminal layout. Top row: 2S 2Q 2O 2M (X) 2G 2E 2C 2A; bottom row: 2T 2R 2P 2N 2L 2J 2H 2F 2D 2B.
  2. 2
    Turn the ignition switch ON.
  3. 3
    Connect terminal 2J of the ABS control module connector (18 pin) to a ground.
  4. 4
    Check the following points.

Fail-safe relay harness check

Fail-safe relay in ABS relay does not click when 2J terminal grounded
ActionCheck fail-safe relay; Check harness between fail-safe relay and ABS control module
Warning light illuminates after grounding 2J terminal
ActionCheck fail-safe relay
1D (BR) terminal of ABS control module connector does not indicate 12V
ActionCheck fail-safe relay; Check harness between fail-safe relay and ABS hydraulic unit

Check ABS relay (fail-safe relay)

  1. 1
    Measure resistance between terminals (c) and (d) of ABS relay connector.
    ABS RELAY internal schematic showing FAIL-SAFE RELAY and MOTOR RELAY with terminals labeled b, d, 9, f, h, a, e, c. Below is the ABS relay connector terminal-position diagram with positions h g e d c a (bottom row) and f, b (top row).
  2. 2
    Check continuity between terminals (a) and (e) and between (b) and (e).
  3. 3
    Apply 12V to terminals between d and c. Check for continuity between terminals (b) and (e) and between (a) and (e).
Resistancebetween terminals (c) and (d)
60-100Ω

Continuity (no voltage applied)

a-e
ContinuityYes
b-e
ContinuityNo

Continuity (12V applied between d and c)

b-e
ContinuityYes
a-e
ContinuityNo
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