Test C: Scan Tool Does Not Communicate With UART Data Line
- Connect scan tool to Data Link Connector (DLC). DLC is located under instrument panel, near steering column. Turn ignition switch to RUN position. If scan tool powers up, go to next step. If scan tool does not power up, perform TEST A: SCAN TOOL DOES NOT POWER UP .
- Using scan tool, attempt to communicate with each module on UART data line circuit. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. If all modules are not communicating with scan tool, go to next step. If any module communicates with scan tool, go to step 6.
- Turn ignition switch to LOCK position. Disconnect Power train Control Module (PCM) harness connector C1. PCM is located in passenger side of engine compartment, in front of strut tower. Check for open or short to ground in PCM battery voltage and ignition voltage circuits. See IDENTIFYING PCM BATTERY VOLTAGE & IGNITION VOLTAGE CIRCUITS table. See Figure. If no problem exists, go to next step. If any problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.IDENTIFYING PCM BATTERY VOLTAGE & IGNITION VOLTAGE CIRCUITS
Terminal No. (Connector) Wire Color Circuit 19 (C1) Pink (1) Ignition 20 (C1) Orange (2) Battery (1) Battery voltage should exist with ignition switch in RUN and START positions. (2) Battery voltage should exist at all times. - Turn ignition switch to LOCK position. Check for open in PCM ground circuits. See IDENTIFYING PCM GROUND CIRCUITS table. If problem does not exist, go to next step. If problem exists, repair as necessary. Ground point is located on lower left front of engine on transaxle stud, near starter. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.IDENTIFYING PCM GROUND CIRCUITS
Terminal No. (Connector) Wire Color Circuit 16 (C1) Black/White Ground 56 (C1) Black/White Ground 57 (C1) Black/White Ground 60 (C1) Black/White Ground - Check for open in Tan wire between DLC terminal No. 9 and PCM harness connector C1 terminal No. 15. If problem does not exist, go to step 8. If problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.
- Check for open or short to ground in non-communicating module battery voltage and ignition voltage circuits. See IDENTIFYING NON-COMMUNICATING MODULE BATTERY VOLTAGE & IGNITION VOLTAGE CIRCUITS table. Electronic brake control module is located behind left side of instrument panel, on brake pedal bracket. See Fig 1. PCM is located in passenger side of engine compartment, in front of strut tower. Sensing and diagnostic module is located under passenger's front seat. If problem does not exist, go to next step. If any problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.IDENTIFYING NON-COMMUNICATING MODULE BATTERY VOLTAGE & IGNITION VOLTAGE CIRCUITS
Terminal No. (Connector) Wire Color Circuit Electronic Brake Control Module (1) A9 (C1) Brown (2) Ignition B12 (C1) Orange (3) Battery Powertrain Control Module (4) 19 (C1) Pink (2) Ignition 20 (C1) Orange (3) Battery Sensing & Diagnostic Module (5) 10 (6) Yellow (7) Ignition (1) For electronic brake control module harness connector terminal identification, refer to illustration. See Fig 2. (2) Battery voltage should exist with ignition switch in RUN position. (3) Battery voltage should exist at all times. (4) For powertrain control module harness connector terminal identification, refer to illustration. See Figure. (5) For sensing and diagnostic module harness connector terminal identification, refer to illustration. See Fig 3. (6) Sensing and diagnostic module only has one 12-pin harness connector. (7) Battery voltage should exist with ignition switch in RUN and START positions. - Turn ignition switch to LOCK position. Check for open in non-communicating module ground circuits. See IDENTIFYING NON-COMMUNICATING MODULE GROUND CIRCUITS table. If problem does not exist, go to next step. If problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.IDENTIFYING NON-COMMUNICATING MODULE GROUND CIRCUITS
Terminal No. (Connector) Wire Color Circuit Electronic Brake Control Module (1)(2) D (C2) Black Ground Powertrain Control Module (3)(4) 16 (C1) Black/White Ground 56 (C1) Black/White Ground 57 (C1) Black/White Ground 60 (C1) Black/White Ground Sensing & Diagnostic Module (5)(6) 6 (7) Black/White Ground (1) For electronic brake control module harness connector terminal identification, refer to illustration. See Fig 2. (2) Electronic brake control module ground point is located in driver's side of engine compartment, on frame rail, below washer fluid lines. See Fig 4. (3) For powertrain control module harness connector terminal identification, refer to illustration. See Figure. (4) Powertrain control module ground point is located on lower left front of engine on transaxle stud, near starter. (5) For sensing and diagnostic module harness connector terminal identification, refer to illustration. See Fig 3. (6) Sensing and diagnostic module ground point is located behind driver's side of instrument panel, on right side of brake pedal bracket. (7) Sensing and diagnostic module only has one 12-pin harness connector. - Turn ignition switch to LOCK position. Disconnect scan tool from DLC (if connected). Disconnect Powertrain Control Module (PCM) harness connectors. PCM is located in passenger side of engine compartment, in front of strut tower. Disconnect Electronic Brake Control Module (EBCM) harness connectors. EBCM is located behind left side of instrument panel, on brake pedal bracket. See Fig 1. Disconnect Sensing and Diagnostic Module (SDM) harness connector. Sensing and diagnostic module is located under passenger's front seat. Check for short to voltage and short to ground in Tan wire between DLC terminal No. 9, and PCM, EBCM and SDM. For circuit and terminal identification, see DATA LINK CONNECTORS article in WIRING DIAGRAMS. If problem does not exist, go to next step. If problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.
- Check for open in Tan wire between DLC terminal No. 9, and PCM, EBCM and SDM. For circuit and terminal identification, see DATA LINK CONNECTORS article in WIRING DIAGRAMS. If problem does not exist, go to next step. If problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.
- Check for poor terminal connection or tension at DLC terminals No. 9 (Tan wire) and No. 5 (Black wire). See Figure. If problem does not exist, go to next step. If problem exists, repair as necessary. After repairs, perform appropriate diagnostic system check for any malfunctioning system(s). See DIAGNOSTIC SYSTEM CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.
- Replace module(s) that would not communicate on UART serial data line.