Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0505 [BP, BP WITH TC] 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.
1		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.
2		No	Go to the next step.
3	VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT? Connect the WDS or equivalent to the DLC-2. Clear the DTC from the PCM memory using the WDS or equivalent. Turn the ignition switch to the ON position (Engine off). Is the same PENDING CODE for this DTC present?	Yes	Go to the next step.
3		No	Intermittent concern exists. Perform the "INTERMITTENT CONCERNS TROUBLESHOOTING". (See INTERMITTENT CONCERN TROUBLESHOOTING .)
4	CLASSIFY INTERMITTENT CONCERN OR CONTINUOUS CONCERN Clear DTC using the WDS or equivalent. Start engine and warm it up completely. Is same DTC detected?	Yes	Go to the next step.
4		No	Go to intermittent concern.
5	INSPECT IAC VALVE CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect IAC valve connector. Check for poor connection (damaged, pulled-out terminals, corrosion, etc.). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 15.
5		No	Go to the next step.
6	INSPECT IAC VALVE Inspect the IAC valve. Is there any malfunction?	Yes	Replace IAC valve, then go to Step 15.
6		No	Go to the next step.
7	DETERMINE IF MALFUNCTION AT POWER SUPPLY CIRCUIT OR CONTROL CIRCUIT Turn the ignition switch to the ON position (Engine off). Measure voltage between IAC valve terminal A (harness-side) and body ground. Is voltage B+ ?	Yes	Malfunction at control circuit. Go to Step 11.
7		No	Malfunction at power supply circuit. Go to the next step.
8	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect PCM connector. Check for poor connection at terminal 2P (damaged, pulled-out terminals, corrosion, etc.). Is there any malfunction?	Yes	Repair terminal, then go to Step 15.
8		No	Go to the next step.
9	INSPECT POWER CIRCUIT FOR SHORT TO GROUND Turn the ignition switch off. Check continuity between IAC valve terminal A (harness-side) and body ground. Is there continuity?	Yes	Repair or replace harness for short to ground, then go to Step 15.
9		No	Go to the next step.
10	INSPECT POWER CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off Disconnect PCM connector. Check continuity between IAC valve terminal A (harness-side) and PCM terminal 2P (harness-side). Is there continuity?	Yes	Repair or replace harness for an open circuit, then go to Step 15.
10		No	Go to Step 15.
11	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off Disconnect PCM connector. Check for poor connection at terminal 2Q (damaged, pulled-out terminals, corrosion, etc.). Is there any malfunction?	Yes	Repair terminal, then go to Step 15.
11		No	Go to the next step.
12	INSPECT CONTROL CIRCUIT FOR SHORT TO POWER Turn the ignition switch to the ON position (Engine off). Measure voltage between IAC valve terminal B (harness-side) and body ground. Is voltage B+ ?	Yes	Repair or replace harness for short to power, then go to Step 15.
12		No	Go to the next step.
13	INSPECT CONTROL CIRCUIT FOR SHORT TO GROUND Turn the ignition switch off. Check continuity between IAC valve terminal B (harness-side) and body ground. Is there continuity?	Yes	Repair or replace harness for short to ground, then go to Step 15.
13		No	Go to the next step.
14	INSPECT CONTROL CIRCUIT MALFUNCTION FOR OPEN CIRCUIT Disconnect PCM connector. Check continuity between IAC valve terminal B (harness-side) and PCM terminal 2Q (harness-side). Is there continuity?	Yes	Repair or replace harness for open circuit, then go to the next step.
14		No	Go to the next step.
15	VERIFY TROUBLESHOOTING OF DTC P0505 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Start the engine and warm it up completely. Is same DTC present?	Yes	Replace PCM, then go to the next step.
15		No	Go to the next step.
16	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE ". (See AFTER REPAIR PROCEDURE .) Is any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
16		No	Troubleshooting completed.