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 P0850 [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 the FREEZE FRAME DATA on the repair order, then go to the next step.
2	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.
2		No	Go to the next step.
3	CLASSIFY HIGH INPUT OR LOW INPUT Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Verify CPP/PNP PID when gear in neutral position. Is CPP/PNP PID always OFF?.	Yes	Go to the next step.
3		No	Go to Step 10.
4	INSPECT NEUTRAL SWITCH CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect neutral switch 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 14.
4		No	Go to the next step.
5	CLASSIFY NEUTRAL SWITCH OR CIRCUIT Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Connect a jumper wire between neutral switch terminals A and B. Is CPP/PNP PID on?	Yes	Go to the next step.
5		No	Go to Step 7.
6	INSPECT NEUTRAL SWITCH Inspect neutral switch. (See NEUTRAL SWITCH INSPECTION .) Is there any malfunction?	Yes	Replace neutral switch, then go to Step 14. (See NEUTRAL SWITCH REMOVAL/INSTALLATION .)
6		No	Go to Step 14.
7	INSPECT NEUTRAL SWITCH GND CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Check continuity between neutral switch terminal A (harness-side) and body GND. Is there continuity?	Yes	Go to the next step.
7		No	Repair or replace harness for open circuit, then go to Step 14.
8	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 14.
8		No	Go to the next step.
9	INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Check continuity between neutral switch terminal B (harness-side) and PCM terminal 31 (harness-side). Is there continuity?	Yes	Go to Step 14.
9		No	Repair or replace harness for open circuit, then go to Step 14.
10	INSPECT NEUTRAL SWITCH CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect neutral switch 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 14.
10		No	Go to the next step.
11	CLASSIFY NEUTRAL SWITCH OR CIRCUIT Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Verify that CPP/PNP PID changes from ON to OFF when neutral switch connector is disconnected. Does CPP/PNP PID change from ON to OFF?	Yes	Go to the next step.
11		No	Go to Step 13.
12	INSPECT NEUTRAL SWITCH Inspect neutral switch. (See NEUTRAL SWITCH INSPECTION .) Is there any malfunction?	Yes	Replace neutral switch, then go to Step 14. (See NEUTRAL SWITCH REMOVAL/INSTALLATION .)
12		No	Go to Step 14
13	INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT FOR SHORT TO GND Turn the ignition switch off. Check continuity between neutral switch terminal B (harness-side) and body GND. Is there continuity?	Yes	Repair or replace harness for short to GND, then go to the next step.
13		No	Go to the next step.
14	VERIFY TROUBLESHOOTING OF DTC P0850 COMPLETED Make sure to reconnect all disconnected connectors. Start engine. Clear the DTC from the PCM memory using the WDS or equivalent. Operate clutch pedal when driving vehicle 30 km/h {18.6 mph} or below 10 times alternately. Is PENDING CODE same as DTC present?	Yes	Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
14		No	Go to the next step.
15	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 .)
15		No	Troubleshooting completed.