LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2017 >> 5 GT, Automatic Trans >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Symptom Troubleshooting - Keyless Entry System >> No. 2 All Keyless Entry System Functions Inoperative >> Diagnostic procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic procedure

NO. 2 ALL KEYLESS ENTRY SYSTEM FUNCTIONS INOPERATIVE (KEYLESS ENTRY SYSTEM) DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 INSPECT BCM POWER SUPPLY FUSES
  • Are the BCM power supply fuses normal?
 Yes Go to the next step.
No Install an appropriate amperage fuse.
2 INSPECT DOOR LATCH SWITCHES, SLIDING DOOR SWITCHES, LIFTGATE LATCH SWITCH INSTALLATION
  • Are the door latch switches, sliding door switches, and the liftgate latch switch installed securely?
 Yes Go to the next step.
No Install the door latch switches, sliding door switches, and the liftgate latch switch securely, then go back to Step 11 of KEYLESS ENTRY SYSTEM PRELIMINARY INSPECTION.
*3 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (NO CONTINUITY BETWEEN FUSE BLOCK AND BCM) OR ELSEWHERE
  • Switch the ignition ON.
  • Measure the voltage at the following BCM terminals:
    • IG1 signal (terminal 4T)
      • Power supply signal (terminal 3J, 5B, 4S)
  • Is the voltage B+?
 Yes Go to the next step.
No Repair the wiring harness between the fuse block and BCM, then go to Step 13.
*4 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (SHORT TO POWER SUPPLY BETWEEN FUSE BLOCK AND BCM, OR BETWEEN BCM AND GROUND) OR ELSEWHERE
  • Switch the ignition OFF (LOCK).
  • Disconnect the BCM connector.
  • Measure the voltage at the following BCM terminal (wiring harness-side):
    • IG1 signal (terminal 4T)
  • Is the voltage B+?
 Yes Repair the malfunctioning wiring harness, then go to Step 13.
No Go to the next step.
*5 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (NO CONTINUITY BETWEEN BCM AND GROUND) OR ELSEWHERE
  • Is there continuity between BCM terminal 2N, 4B, 4D and ground?
 Yes Go to the next step.
No Repair the wiring harness between the BCM and ground, then go to Step 13.
6 INSPECT IF MALFUNCTION IS IN DOOR, LIFTGATE LATCH SWITCH SIGNALS OR ELSEWHERE
  • Monitor following BCM (door, liftgate latch switch) PID using the M-MDS.
    • TR/LG_SW (Liftgate latch switch)
    • DRSW_P (Passenger's door latch switch)
    • DRSW_D (Driver's door latch switch)
    • DRSW_LR (Sliding door switch (LH))
      • DRSW_RR (Sliding door switch (RH))
  • Are monitored PID values normal?
 Yes Go to the next Step.
No
  • Inspect for open or short circuit in wiring harness between BCM and suspected door latch switches, sliding door switches, and the liftgate latch switch.
7 INSPECT BCM OR WIRING HARNESS (BETWEEN BCM AND DOOR LATCH SWITCHES, SLIDING DOOR SWITCHES, LIFTGATE LATCH SWITCH FOR CONTINUITY)
  • Open and close all doors.
  • Verify continuity between BCM terminals 6G, 6H, 6K, 6E, 6F and ground.
  • Are there continuities followings?

    Door latch switches/Sliding door switches (Terminal 6G, 6H, 6K, 6E):

    • Open: Not continuity
      • Close: Continuity

    Liftgate latch switch (Terminal 6F):

    • Open: Continuity
      • Close: Not continuity
 Yes Replace the BCM and reprogram the keyless entry remote transmitter ID code, then go to the next step.
No Repair the wiring harness between the BCM and door latch switches, sliding door switches, and the liftgate latch switch then go to the next step.
8 INSPECT POWER SUPPLY FUSE
  • Is the keyless receiver power supply fuse normal?
 Yes Go to the next step.
No Inspect and repair short to GND in wiring harness at keyless receiver power supply circuit install an appropriate amperage fuse, then go to step 13.
9 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (NO CONTINUITY BETWEEN FUSE BLOCK AND KEYLESS RECEIVER) OR ELSEWHERE
  • Measure the voltage at the following keyless receiver terminal:
    • B+ signal (terminal A)
  • Is the voltage B+?
 Yes Go to the next step.
No Repair the wiring harness between the fuse block and keyless receiver, then go to Step 13.
10 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (NO CONTINUITY BETWEEN KEYLESS RECEIVER AND GROUND) OR ELSEWHERE
  • Is there continuity between keyless receiver terminal E and ground?
 Yes Go to the next step.
No Repair the wiring harness between the keyless receiver and ground, then go to Step 13.
11 INSPECT IF MALFUNCTION IS IN WIRING HARNESS (NO CONTINUITY BETWEEN KEYLESS RECEIVER AND BCM) OR ELSEWHERE
  • Disconnect the keyless receiver connector and BCM connector.
  • Is there continuity between the following terminals?
    • 4K (BCM connector)-D (keyless receiver connector)
 Yes Go to the next step.
No Repair the wiring harness between the keyless receiver and BCM, then go to Step 13.
12
  • Measure the signal wave pattern for keyless receiver terminal D using an oscilloscope while the keyless entry remote transmitter is operated with the key not inserted into the ignition key cylinder.
  • Does the wave pattern change when the keyless entry remote transmitter is operated?
    NOTE:
    • Perform the oscilloscope setting using 0.5 V/DIV (Y), 100 ms/DIV (X), DC range.
 Yes Replace the BCM, then go to the next step. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION .)
No Replace the keyless receiver, then go to the next step.
(See KEYLESS RECEIVER REMOVAL/INSTALLATION .)
13 REINSPECT MALFUNCTION SYMPTOM AFTER REPAIR
  • Does the keyless entry system operate properly?
 Yes Troubleshooting completed. Explain repairs to the customer.
No Reinspect the malfunction symptoms, then repeat from Step 1 if the malfunction recurs.
scientia non olet · About LEMON Manuals