LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2011 >> RX-8 R3, 1.3 4 >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic [Engine Control System] >> DTC P2257
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P2257

DTC P2257 AIR pump relay control circuit low
DETECTION CONDITION 
  • The PCM monitors the AIR pump relay control voltage when the AIR pump is not operating. If the control voltage is less than the specification, the PCM determines that the AIR pump relay control circuit voltage is low.

Diagnostic support note 
  • This is a continuous monitor (AIR system).
  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • AIR pump relay terminal malfunction
  • Short to ground or open circuit in AIR pump relay power supply circuit
    • Short to ground in wiring harness between main relay terminal C and AIR pump relay terminal D
    • AIR pump relay related fuse malfunction
    • Open circuit in wiring harness between main relay terminal C and AIR pump relay terminal D
  • Short to ground in wiring harness between AIR pump relay terminal A and PCM terminal 1G
  • AIR pump relay malfunction
  • PCM connector or terminals malfunction
  • Open circuit in wiring harness between AIR pump relay terminal A and PCM terminal 1G
  • PCM malfunction
G07878155
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 (AIR system 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 REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
 Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT AIR PUMP RELAY CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Remove the AIR pump relay.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the terminal, then go to Step 9.
No Go to the next step.
4 INSPECT AIR PUMP RELAY POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT 
  • AIR pump relay is removed.
  • Turn the ignition switch to the ON position (engine off).
  • Measure the voltage between AIR pump relay terminal D (wiring harness-side) and body ground.
  • Is the voltage B+  ?
 Yes Go to the next step.
No Inspect the AIR pump relay related fuse.
  • If the fuse is melt:
    • Repair or replace the wiring harness for a possible short to ground.
    • Replace the fuse.
  • If the fuse is deterioration:
    • Replace the fuse.
  • If the fuse is normal:
    • Repair or replace the wiring harness for a possible open circuit

Go to Step 9.
5 INSPECT AIR PUMP RELAY CONTROL CIRCUIT FOR SHORT TO GROUND 
  • ASR pump relay is removed.
  • Turn the ignition switch off.
  • Inspect for continuity between AIR pump relay terminal A (wiring harness-side) and body ground.
  • Is there continuity?
 Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

If the short to ground circuit could not be detected:
Go to Step 9.
No Go to the next step.
6 INSPECT AIR PUMP RELAY 
 Yes Replace the AIR pump relay, then go to Step 9.
(See RELAY LOCATION ).
No Go to the next step.
7 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
8 INSPECT AIR PUMP RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT 
  • AIR pump relay is removed and PCM connector is disconnected.
  • Inspect for continuity between AIR pump relay terminal A (wiring harness-side) and PCM terminal 1G (wiring harness-side).
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P2257 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.

    (See AFTER REPAIR PROCEDURE ).

  • Perform the KOEO or KOER self test.

    (See KOEO/KOER SELF TEST ).

  • Is the PENDING CODE same as 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.
scientia non olet · About LEMON Manuals