LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2006 >> MX-5 Miata Base >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic [Engine Control System] >> DTC P0505 >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

DTC P0505 DIAGNOSTIC PROCEDURE TABLE

STEP INSPECTION ACTION
1 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.
2 VERIFY RELATED PENDING OR STORED DTC 
  • Turn the ignition switch off then to the ON position. (Engine off)
  • Verify pending code or stored DTCs using the WDS or equivalent.
  • Does DTC P0506, P0507, P0638, P2101, P2107, P2108, P2109, P2112 or P2119 presents?
Yes Perform the applicable DTC troubleshooting.
(See DTC TABLE  .)
No Go to the next step.
3 INSPECT ELECTRONIC THROTTLE CONTROL SYSTEM OPERATION  Yes Go to the next step.
No Repair or replace malfunctioning part, according to inspection results.
Then go to Step 9.
4 INSPECT A/C MAGNETIC CLUTCH OPERATION 
NOTE:
  • The following test should be performed for the A/C. Go to the next step for vehicles without A/C
  • Turn the fan switch off.
  • Is the magnetic clutch still on?
Yes Go to "A/C ALWAYS ON /A/C COMPRESSOR RUNS CONTINUOUSLY." of ENGINE SYMPTOM TROUBLESHOOTING then go to Step 9.
(See ENGINE SYMPTOM TROUBLESHOOTING .)
No Go to the next step.
5 INSPECT GENERATOR CONTROL CIRCUIT MALFUNCTION 
  • Apply electrical load.
  • Is the engine speed increased?
Yes Go to the next step.
No Repair short to power supply in generator control circuit, then go to Step 9.
6 INSPECT AIR CLEANER ELEMENT 
  • Remove air cleaner element with the engine running.
  • Is the engine speed increased?
Yes Clean or replace the air cleaner element, then go to Step 9.
(See INTAKE AIR SYSTEM REMOVAL/INSTALLATION .)
No Go to the next step.
7 INSPECT THROTTLE BODY PASSAGE 
  • Is the throttle body clogged?
Yes Clean or replace the throttle body passage, then go to Step 9.
No Go to the next step.
8 INSPECT ENGINE COMPRESSION  Yes Go to the next step.
No Overhaul the engine, then go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P0505 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC using the WDS or equivalent.
  • 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 troubleshooting.
(See DTC TABLE  .)
No Troubleshooting completed.