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 P0123 [AJ] 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	INSPECT THROTTLE BODY CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect throttle body connector. Check for poor connection (such as damaged, pulled-out pins, and corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
3		No	Go to the next step.
4	INSPECT TP SENSOR NO. 1 SIGNAL CIRCUIT FOR SHORT TO POWER Turn the ignition switch to the ON position. Measure voltage between throttle body terminal F (harness-side) and body GND. Is voltage B+?	Yes	Repair or replace harness for short to power, then go to Step 8.
4		No	Go to the next step.
5	INSPECT TP SENSOR NO. 1 Inspect TP sensor No. 1. (See THROTTLE POSITION (TP) SENSOR INSPECTION .) Is there any malfunction?	Yes	Replace throttle body, then go to Step 8. (See INTAKE AIR SYSTEM REMOVAL/INSTALLATION .)
5		No	Go to the next step.
6	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect PCM connector. Check for poor connection (such as damaged, pulled-out pins, and corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
6		No	Go to the next step.
7	INSPECT TP SENSOR NO. 1 GND CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Check continuity between throttle body terminal E (harness-side) and PCM terminal 13 (harness-side). Is there continuity?	Yes	Go to the next step.
7		No	Repair or replace harness for open circuit, then go to the next step.
8	VERIFY TROUBLESHOOTING OF DTC P0123 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Turn the ignition switch to the ON position. Is same DTC present?	Yes	Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
9		No	Troubleshooting completed.