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Home >> Mazda >> 2021 >> MX-5 Miata Club, Standard Trans >> Repair and Diagnosis >> Body & Frame >> Door Locks >> On-Board Diagnostic - Retractable Fastback Control Module >> DTC U0030-87: Communication Error With Power Window Main Switch [Retractable Hardtop Control Module] >> Diagnostic Procedure
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Diagnostic Procedure

DTC U0030:87 (RETRACTABLE HARDTOP CONTROL MODULE) DIAGNOSTIC PROCEDURE

Step Inspection Action
1 VERIFY OTHER RETRACTABLE HARDTOP CONTROL MODULE DTCs
Yes Replace the retractable hardtop control module, then go to Step 5.
(See RETRACTABLE HARDTOP CONTROL MODULE REMOVAL/INSTALLATION .)
No Go to the next step.
2 INSPECT POWER WINDOW MAIN SWITCH CIRCUIT FOR SHORT TO GROUND
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the retractable hardtop control module and power window main switch connectors.
  • Inspect for continuity between the following terminal (wiring harness-side) and body ground:
    • Power window main switch terminal 1J
  • Is there continuity?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
  • Retractable hardtop control module terminal 4AD and power window main switch terminal 1J

If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Repair or replace the malfunctioning part.

If there is no common connector:
  • Repair or replace the wiring harness which has a short to ground.

    Go to Step 5.

No Go to the next step.
3 INSPECT POWER WINDOW MAIN SWITCH CIRCUIT FOR OPEN CIRCUIT
  • Verify that the retractable hardtop control module and power window main switch connectors are disconnected.
  • Inspect the wiring harness for continuity between the following terminals (wiring harness-side):
    • Retractable hardtop control module terminal 4AD and power window main switch terminal 1J
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
  • Retractable hardtop control module terminal 4AD and power window main switch terminal 1J

If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

If there is no common connector:
  • Repair or replace the wiring harness which has an open circuit.

    Go to Step 5.

4 INSPECT POWER WINDOW MAIN SWITCH
Yes Go to the next step.
No Replace the power window main switch, then go to the next step.
(See POWER WINDOW MAIN SWITCH REMOVAL/INSTALLATION .)
5 VERIFY THAT REPAIRS HAVE BEEN COMPLETED
Yes Repeat the inspection from Step 1.
No Go to the next step.
6 VERIFY IF OTHER DTCs DISPLAYED
  • Are any other DTCs displayed?
Yes Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.
(See DTC TABLE [RETRACTABLE HARDTOP CONTROL MODULE] .)
No DTC troubleshooting completed.