Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

Step	Inspection		Action
1	INSPECT TCM CONNECTOR CONDITION Switch the ignition to off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the TCM connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
1		No	Repair or replace the connector, then go to Step 5.
2	INSPECT START STOP UNIT CONNECTOR CONDITION Disconnect the start stop unit connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
2		No	Repair or replace the connector, then go to Step 5.
3	INSPECT TCM CIRCUIT FOR SHORT TO POWER SUPPLY Reconnect all the disconnected connectors. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Operate the selector lever to positions P or N. Measure the voltage at start stop unit terminal 1F (vehicle wiring harness side). Is the voltage 1.0 V or less?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness which is shorted to power supply, then go to Step 5.
4	PERFORM DTC INSPECTION AND VERIFY IF MALFUNCTIONING PART IS TRANSAXLE RANGE SENSOR Clear DTC for the start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT] .) Switch the ignition ON (engine off). Perform the following work five or more times. Operate the selector lever to positions P or N and wait for 1 s or more . Operate the selector lever to positions R or D and wait for 1 s or more . Operate the selector lever to positions P or N. Perform the DTC inspection for the start stop unit using the M-MDS. (See DTC INSPECTION [START STOP UNIT] .) Is DTC P0850:23 displayed?	Yes	Replace the TCM, then go to the next step. (See CONTROL VALVE BODY REMOVAL/INSTALLATION [FW6A-EL, FW6AX-EL] .)
4		No	Go to Step 6.
5	VERIFY THAT REPAIRS HAVE BEEN COMPLETED Reconnect all the disconnected connectors. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Clear DTC for the start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT] .) Switch the ignition ON (engine off). Perform the following work five or more times. Operate the selector lever to positions P or N and wait for 1 s or more . Operate the selector lever to positions R or D and wait for 1 s or more . Operate the selector lever to positions P or N. Perform the DTC inspection for the start stop unit using the M-MDS. (See DTC INSPECTION [START STOP UNIT] .) Is DTC P0850:23 displayed?	Yes	Replace the start stop unit, then go to the next step. (See START STOP UNIT REMOVAL/INSTALLATION .)
5		No	Go to the next step.
6	VERIFY IF OTHER DTCs DISPLAYED Are any other DTCs displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [START STOP UNIT] .)
6		No	DTC troubleshooting completed.