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Home >> Mazda >> 2014 >> MX-5 Miata Club, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic [Engine Control System LF] >> DTC P2502

DTC P2502

DTC P2502  Charging system voltage problem 
DETECTION CONDITION 
  • The PCM judges generator output voltage is above 17 V  or battery voltage is below 11 V  for 5s  during the engine running.

Diagnostic support note 
  • This is a continuous monitor (other).
  • The MIL does not illuminate.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Short to ground in generator power supply circuit
    • Short to ground in wiring harness between battery positive terminal and generator terminal B
    • Generator power supply circuit related fuse malfunction Battery malfunction
  • Generator is poorly connected
  • Battery is poorly connected
  • Open circuit in wiring harness between battery positive terminal and generator terminal B
  • Generator malfunction
  • PCM malfunction
G07877657
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (other related) been recorded?
Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2 VERIFY RELATED SERVICE BULLETINS AVAILABILITY 
  • Verify related Service Bulletins availability.
  • Is any related Service Bulletins available?
Yes Perform the repair or diagnosis according to the available Service Bulletins.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT FUSE 
  • Turn the ignition switch off.
  • Remove the MAIN fuse.
  • Inspect the fuse.
  • Is there any malfunction?
Yes If the fuse is melt:

If the fuse is deterioration:
  • Replace the fuse.

Go to Step 9.
No Install the fuse, then go to the next step.
4 INSPECT BATTERY 
Yes Recharge or replace the battery, then go to Step 9.
(See BATTERY RECHARGING [LF] ).
(See BATTERY REMOVAL/INSTALLATION [LF] ).
No Go to the next step.
5 INSPECT POOR INSTALLATION OF GENERATOR TERMINAL 
  • Turn the ignition switch off.
  • Inspect for looseness of generator terminal B installation nut.
  • Is the nut loose?
Yes Tighten generator terminal B installation nut, then go to Step 9.
No Go to the next step.
6 INSPECT POOR INSTALLATION OF BATTERY POSITIVE TERMINAL 
  • Inspect for looseness of battery positive terminal.
  • Is the terminal loose?
Yes Connect the battery positive terminal correctly, then go to Step 9.
No Go to the next step.
7 INSPECT BATTERY CHARGING CIRCUIT FOR OPEN CIRCUIT 
  • Measure the voltage between generator terminal B (wiring harness-side) and body ground.
  • Is the voltage B+  ?
Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to Step 9.
8 INSPECT GENERATOR 
Yes Replace the generator, then go to the next step.
(See GENERATOR REMOVAL/INSTALLATION [LF] ).
No Go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P2502 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.
  • Perform the KOER self test.

    (See KOEO/KOER SELF TEST ).

  • Is the same DTC present?
Yes Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION ).
No Go to the next step.
10 VERIFY AFTER REPAIR PROCEDURE 
Yes Go to the applicable DTC inspection.
(See DTC TABLE ).
No DTC troubleshooting completed.