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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 330 (ON-BOARD DIAGNOSTIC (ENGINE CONTROL SYSTEM (L3))DTC P2123DIAGNOSTIC PROCEDURE
2008 Mazda 6 s Sport, 4D Hatchback, Standard

Diagnostic procedure

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Diagnostic procedure
WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
DTC P2123 [L3] DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA HAS BEEN RECORDED 
  • Has FREEZE FRAME DATA been recorded?
 Yes Go to the next step.
No Record FREEZE FRAME DATA on repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Check for related Service Bulletins and/or online 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 APP SENSOR CONNECTOR 
  • Turn the ignition switch off.
  • Verify that the APP sensor connector is connected securely.
  • Is connector normal?
 Yes Go to the next step.
No Connect the connector securely, then go to Step 10.
4 INSPECT APP SENSOR CONNECTOR FOR POOR CONNECTION 
  • Disconnect APP sensor connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace suspected terminal, then go to Step 10.
No Go to the next step.
5 INSPECT APP SENSOR 
 Yes Go to the next step.
No Replace APP sensor, then go to Step 10.
6 INSPECT APP1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Turn ignition switch to ON (Engine off).
  • Measure voltage between APP sensor terminal F (harness-side) and body ground.
  • Is voltage above 4.5 V (1) , 4.8 V (2) ? 
 Yes Repair or replace short to power supply. Then, go to Step 10.
No Go to the next step.
7 VERIFY APP SENSOR GROUND CIRCUIT FOR OPEN CIRCUIT 
  • Disconnect PCM connector.
  • Inspect continuity between APP sensor terminal E (harness side) and PCM terminal 17(1), 3A(2) (harness side).
  • Is there continuity?
 Yes Repair or replace open circuit between APP sensor terminal F (harness-side) and PCM connector terminal 43(1), 3D(2) (harness-side). Then, go to Step 10.
No Go to the next step.
8 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair terminal, then go to Step 10.
No Go to the next step.
9 VERIFY TP SIGNAL CIRCUIT FOR SHORT TO CONSTANT VOLTAGE CIRCUIT 
  • Inspect continuity between throttle body terminals D and F (harness side).
  • Is there continuity?
 Yes Repair or replace suspected harness, then go to the next step.
No Go to the next step.
10 VERIFY TROUBLESHOOTING OF DTC P2123 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Turn ignition switch to ON (Engine off).
  • Clear the DTC from the PCM memory using the WDS or equivalent.
  • Start engine and warm it up completely.
  • Is same DTC present?
 Yes Replace PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION .)
No Go to the next step.
11 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No Troubleshooting completed.
(1) California emission regulation applicable ATX model
(2) Except for California emission regulation applicable ATX model
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.