Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0871 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	INSPECT FOR DTC Turn the ignition switch to the ON position (engine off). Inspect for DTCs. Are any other DTCs output?	Yes	Follow the applicable DTC inspection procedure. (See DTC TABLE .)
3		No	Go to the next step.
4	INSPECT AT SOLENOID VALVE CONNECTOR FOR POOR CONNECTION Turn the ignition switch to the LOCK position. Disconnect the AT solenoid valve connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Are the connector and terminals normal?	Yes	Go to the next step.
4		No	Repair or replace the connector and/or terminal, then go to Step 15.
5	INSPECT TCM CONNECTOR FOR POOR CONNECTION Disconnect the TCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Are the connector and terminals normal?	Yes	Go to the next step.
5		No	Repair or replace the connector and/or terminal, then go to Step 15.
6	INSPECT TCM CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the TCM (wiring harness-side) terminal 2H and AT solenoid valve connector (wiring harness-side) terminal L. Is there continuity?	Yes	Go to the next step.
6		No	Repair or replace the wiring harness, then go to Step 15.
7	INSPECT TCM CIRCUIT FOR SHORT TO GROUND Inspect for continuity between the TCM (wiring harness-side) terminal 2H and body ground. Is there continuity?	Yes	Repair or replace the wiring harness, then go to Step 15.
7		No	Go to the next step.
8	INSPECT CONTROL VALVE BODY CONNECTOR FOR POOR CONNECTION Disconnect the control valve body connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Are the connector and terminals normal?	Yes	Go to the next step.
8		No	Repair or replace the connector and/or terminal, then go to Step 15.
9	INSPECT AT SOLENOID VALVE CONNECTOR CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the AT solenoid valve connector (transmission case side) terminal L and control valve body (wiring harness-side) terminal B. Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness, then go to Step 15.
10	INSPECT TCM CIRCUIT FOR SHORT TO GROUND Inspect for continuity between the AT solenoid valve connector (transmission case-side) terminal L and body ground. Is there continuity?	Yes	Repair or replace the wiring harness, then go to Step 15.
10		No	Go to the next step.
11	INSPECT OIL PRESSURE SWITCH F CONNECTOR FOR POOR CONNECTION Disconnect the oil pressure switch F connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Are the connector and terminals normal?	Yes	Go to the next step.
11		No	Repair or replace the connector and/or terminal, then go to Step 15.
12	INSPECT CONTROL VALVE BODY CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the control valve body connector terminal B (part-side) and oil pressure switch F (wiring harness-side) terminal A. Is there continuity?	Yes	Go to the next step.
12		No	Repair or replace the wiring harness, then go to Step 15.
13	INSPECT CONTROL VALVE BODY CIRCUIT FOR SHORT TO GROUND Inspect for continuity between the control valve body connector (wiring harness-side) terminal L and body ground. Is there continuity?	Yes	Repair or replace the wiring harness, then go to Step 15.
13		No	Go to the next step.
14	INSPECT OIL PRESSURE SWITCH F Inspect oil pressure switch F. (See OIL PRESSURE SWITCH INSPECTION .) Is the oil pressure switch F normal?	Yes	Go to the next step.
14		No	Replace the oil pressure switch F, then go to the next step. (See OIL PRESSURE SWITCH REMOVAL/INSTALLATION .)
15	VERIFY TROUBLESHOOTING OF DTC P0871 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the TCM memory using the WDS or equivalent. Drive the vehicle and make sure that the gears shift smoothly from 1GR to 4GR. Is the same DTC present?	Yes	Replace the TCM, then go to the next step. (See TCM REMOVAL/INSTALLATION .)
15		No	Go to the next step.
16	VERIFY AFTER REPAIR PROCEDURE Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
16		No	DTC troubleshooting completed.