DTC P026A:00 [PCM (SKYACTIV-X)]

Description	Water-cooled charge air cooler: Function malfunction
Detection condition	Determination conditions	• If any of the following conditions is met: ― The temperature detected by the boost air temperature sensor is higher than the specified value for the estimated gas temperature of the water-cooled charge air cooler outlet. ― The temperature detected by ECT sensor No.3 is the specified value or more.
	Preconditions	• Supercharger clutch is engaged • Engine speed: 500 rpm or more^1 • Battery voltage: 8 V or more^1 ^*1: Standard can be verified by displaying PIDs using M-MDS
	Drive cycle	• 1
	Self test type	• CMDTC self test
	Sensor used	• IAT sensor No.1 • IAT sensor No.2 • MAP sensor • Boost air temperature sensor • Boost pressure sensor • Supercharger speed sensor • ECT Sensor No.3
Fail-safe function	• Inhibits the boost system. • Stops the EGR control.
Vehicle status when DTCs are output	• Not applicable
Possible cause	• Boost air temperature sensor malfunction • ECT Sensor No.3 malfunction • Water-cooled charge air cooler malfunction ― Crushed fin, foreign matter penetration • Electric water pump malfunction (poor pumping of engine coolant) • PCM malfunction

• If the cooling efficiency of the water-cooled charge air cooler is extremely low or the engine coolant temperature passing through the water-cooled charge air cooler is extremely high, the PCM determines that the cooling system is malfunctioning and stores a DTC.

1. Warm up the engine to allow the engine coolant temperature to reach 80 °C {176 °F} or more.

2. Try to reproduce the malfunction by driving the vehicle for 5 min based on the values in the freeze frame data/snapshot data.

Step	Inspection	Results	Action
1	PURPOSE: VERIFY RELATED REPAIR INFORMATION OR SERVICE INFORMATION AVAILABILITY • Verify related Service Bulletins, on-line repair information, or Service Information availability. • Is any related Information available?	Yes	Perform repair or diagnosis according to the available information. • If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	PURPOSE: RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION • Record the freeze frame data/snapshot data. Note • Recording can be facilitated using the screen capture function of the PC.	—	Go to the next step.
3	PURPOSE: INSPECT FOR OTHER RELATED DTCs • Perform the DTC inspection for the PCM. (See DTC INSPECTION.) • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-X)].) Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
3		No	Go to Troubleshooting Diagnostic Procedure to perform the procedure from Step 1.

• Repair completion verification

Step	Inspection	Results	Action
1	PURPOSE: INSPECT BOOST AIR TEMPERATURE SENSOR FOR MALFUNCTION • Inspect the applicable part. (See BOOST AIR TEMPERATURE SENSOR INSPECTION [SKYACTIV-X 2.0].) • Is the part normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See BOOST AIR PRESSURE SENSOR/BOOST AIR TEMPERATURE SENSOR REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
2	PURPOSE: INSPECT ECT SENSOR No.3 FOR MALFUNCTION • Inspect the applicable part. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-X 2.0].) • Is the part normal?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
3	PURPOSE: INSPECT WATER-COOLED CHARGE AIR COOLER FOR MALFUNCTION • Inspect the applicable part. (See WATER-COOLED CHARGE AIR COOLER INSPECTION [SKYACTIV-X 2.0].) • Is the part normal?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See WATER-COOLED CHARGE AIR COOLER REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
4	VERIFY IF POOR COOLING OF ENGINE COOLANT AFFECTS DIAGNOSTIC RESULTS • Inspect the following part. ― Water-cooled charge air cooler • Crushed fin, foreign matter penetration • Is the part normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See WATER-COOLED CHARGE AIR COOLER REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED • Install/connect the part removed/disconnected during the troubleshooting procedure. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Replicate the vehicle conditions at the time the DTC was detected using the following procedure. ― Implement the repeatability verification procedure. (See Repeatability Verification Procedure.) • Perform the DTC inspection for the PCM. (See DTC INSPECTION.) • Is the same pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.

Mazdamanuals.com