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 P0480 [BP, BP WITH TC] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	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.
1		No	Go to the next step.
2	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.
2		No	Intermittent concern exists. Perform the "INTERMITTENT CONCERNS TROUBLESHOOTING". (See INTERMITTENT CONCERN TROUBLESHOOTING .)
3	INSPECT FAN RELAY NO.1 CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect fan relay No.1 connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion, etc.). Is there malfunction?	Yes	Repair or replace terminal and/or connector, then go to Step 10.
3		No	Go to the next step.
4	INSPECT FAN RELAY NO.1 POWER CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch to the ON position (Engine off). Measure voltage between fan relay No.1 terminal A (harness side) and body ground. Is voltage B+ ?	Yes	Go to the next step.
4		No	Replace or replace harness for an open circuit, then go to Step 10.
5	INSPECT FAN RELAY NO.1 Inspect fan relay No.1 Is fan relay No.1 okay?	Yes	Go to the next step.
5		No	Replace fan relay No.1, then go to Step 10.
6	INSPECT FAN RELAY NO.1 CONTROL CIRCUIT FOR SHORT TO POWER Measure voltage between fan relay No.1 terminal E (harness-side) and body ground. Is voltage B+ ?	Yes	Repair or replace harness for short to power, then go to Step 10.
6		No	Go to the next step.
7	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect PCM connector. Inspect for poor connection (such as damaged/ pulled-out pins, corrosion). Is there malfunction?	Yes	Repair or replace terminal and/or connector, then go to Step 10.
7		No	Go to the next step.
8	INSPECT FAN RELAY NO.1 CONTROL CIRCUIT FOR SHORT TO GROUND Inspect continuity between fan relay No.1 terminal E (harness side) and body ground. Is there continuity?	Yes	Repair or replace harness for short to ground, then go to Step 10.
8		No	Go to the next step.
9	INSPECT FAN RELAY NO.1 CONTROL CIRCUIT FOR OPEN CIRCUIT Inspect continuity between fan relay No.1 terminal E (harness-side) and PCM terminal 2B (harness-side). Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace harness for an open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0480 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Access ECT PID. Start engine and warm up it until ECT PID above 100 °C {212 °F} Retrieve any DTC. Is same DTC present?	Yes	Replace PCM, then go to the next step.
10		No	Go to the next step.
11	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 .)
11		No	Troubleshooting completed.