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Test 8: No Module/Network Communication - SCP Link

WARNING: This page is about a different car, the 1999 Mazda B4000, 1999 Mazda B3000, and 1999 Mazda B2500. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If test results indicate PCM is faulty, always check for any engine performance related Diagnostic Trouble Codes (DTCs) prior to replacing PCM. If any DTCs exist, service DTCs as necessary and retest. See TROUBLE SHOOTING article in ENGINE PERFORMANCE.
  1. Turn ignition switch to OFF position. Inspect Data Link Connector (DLC) for damage. DLC is located below driver's side of instrument panel, to the right of steering column. If connector is okay, go to next step. If connector is damaged, repair as necessary and retest system for normal operation.
  2. Disconnect Powertrain Control Module (PCM) 104-pin harness connector. Measure resistance of Tan/Orange wire between terminal No. 16 at PCM harness connector and terminal No. 2 at DLC. See Figure and Figure . On vehicles not equipped with Passive Anti-Theft System (PATS), if resistance is 5 ohms or less, go to next step. On vehicles equipped with PATS, if resistance is 5 ohms or less, go to step  6.

    On vehicles not equipped with PATS, if resistance is greater than 5 ohms, go to TEST 5: POWERTRAIN CONTROL MODULE (PCM) DOES NOT RESPOND TO NGS TESTER . On vehicles equipped with PATS, if resistance is greater than 5 ohms, repair open in Tan/Orange wire between PCM and DLC. Retest system for normal operation.

  3. Ensure PCM is disconnected. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, go to next step. If voltage is not indicated at any terminal, repeat self-test. See DIAGNOSTIC PROCEDURE SEQUENCE  under COMMUNICATIONS NETWORK DIAGNOSTICS.

  4. Disconnect 42-pin harness connector (X-124). Turn ignition switch to ON position. Ensure PCM is disconnected. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, go to next step. If voltage is not indicated at any terminal, repair Tan/Orange wire and/or Pink/Light Blue wire between 42-pin harness connector (X-124) and PCM. Retest system for normal operation.

  5. Turn ignition switch to OFF position. Disconnect in-line harness connector (X-136). Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is not indicated at any terminal, repair Tan/Orange wire and/or Pink/Light Blue wire between harness connector X-136 and DLC. If voltage is indicated at any terminal, repair Tan/Orange wire and/or Pink/Light Blue wire between harness connector X-136 and 42-pin in-line harness connector (X-124). Retest system for normal operation.

  6. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, go to next step. If voltage is not indicated at any terminal, repeat self-test. See DIAGNOSTIC PROCEDURE SEQUENCE  under COMMUNICATIONS NETWORK DIAGNOSTICS. Retest system for normal operation.

  7. Disconnect PATS module harness connector. Ensure PCM harness connector is firmly connected. Turn ignition switch to ON position. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, go to next step. If voltage is not indicated at any terminal, replace PATS module. Retest system for normal operation.

  8. Turn ignition switch to OFF position. Disconnect 42-pin harness connector (X-124). See Figure through Figure . Turn ignition switch to ON position. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, go to next step. If voltage is not indicated at any terminal, repair wire(s) in question between in-line harness connector and PCM harness connector. See WIRING DIAGRAMS . Retest system for normal operation.

  9. Turn ignition switch to OFF position. Disconnect 40-pin bulkhead harness connector (X-136), located at left rear of engine compartment. Turn ignition switch to ON position. Measure voltage between the following specified DLC terminals. See Figure.
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 4 (Black wire).
    • Terminal No. 2 (Tan/Orange wire) and terminal No. 16 (Orange wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 4 (Black wire).
    • Terminal No. 10 (Pink/Light Blue wire) and terminal No. 16 (Orange wire).

    If voltage is indicated at any terminal, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between 40-pin bulkhead harness connector, PATS module harness connector, and DLC. If voltage is not indicated in any terminal, repair Tan/Orange wire and/or Pink/Light Blue wire as necessary between 40-pin bulkhead harness connector (X-136) and 42-pin harness connector (X-124). Retest system for normal operation.

Fig 1: PCM Harness Connector Terminals
G98H04916Courtesy of MAZDA MOTORS CORP.
Fig 2: 42-Pin Harness Connector X-124 Terminals (Male Half Of Connector Shown)
G98J04917Courtesy of MAZDA MOTORS CORP.
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