Mazdamanuals.com

DTC P2251:00 [PCM (SKYACTIV-X)]

Home  id0102u9851300

Note

•  To determine the malfunctioning part, proceed with the diagnostics from "Function Inspection Using M-MDS".

Details On DTCs

Description	Open circuit between A/F sensor terminal D and PCM terminal 1S
Detection condition	Determination conditions	•  The following conditions are met: ―  A/F sensor element impedance is specified value or more ―  A/F sensor terminal F voltage (B+ terminal) is less than specified value or unstable.
	Preconditions	•  Battery voltage: 11—18 V*1 •  A/F sensor is activated. •  The following DTCs are not detected: ―  A/F sensor terminal F voltage (B+ terminal) is less than specified value: •  A/F sensor heater: P0031:00 and P0032:00 ―  A/F sensor terminal F voltage (B+ terminal) is unstable: •  Internal PCM malfunction: P064D:00 *1: Standard can be verified by displaying PIDs using M-MDS
	Drive cycle	•  2
	Self test type	•  CMDTC self test, KOER self test
	Sensor used	•  A/F sensor
Fail-safe function	•  Inhibits the EGR control.
Vehicle status when DTCs are output	•  Not applicable
Possible cause	•  A/F sensor connector or terminals malfunction •  PCM connector or terminals malfunction •  Open circuit in A/F sensor signal circuit •  A/F sensor malfunction •  PCM malfunction

Function Explanation (DTC Detection Outline)

Repeatability Verification Procedure

PID Item/Simulation Item Used In Diagnosis

PID/DATA monitor item table

Function Inspection Using M-MDS

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.
		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 A/F SENSOR CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location. Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
4	PURPOSE: INSPECT PCM CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location. Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
5	PURPOSE: INSPECT A/F SENSOR SIGNAL CIRCUIT FOR OPEN CIRCUIT •  Inspect the applicable circuit for open circuit. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location. Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
6	PURPOSE: DETERMINE INTEGRITY OF A/F SENSOR •  Start the engine and warm it up completely. •  Access the A/F_SEN_CUR PID using the M-MDS. (See PID/DATA MONITOR INSPECTION.) •  Drive the vehicle under the following conditions. Warning •  When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. •  While performing this step, always operate the vehicle in a safe and lawful manner. ―  After increasing the engine speed to 3,000 rpm, decelerate using engine braking. •  Is the displayed PID value as follows? ―  A/F_SEN_CUR: 0.25 mA or more	Yes	Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
		No	Go to the next step.
7	PURPOSE: VERIFY CONNECTOR CONNECTIONS •  Access the A/F_SEN_CUR PID using the M-MDS. (See PID/DATA MONITOR INSPECTION.) •  Does the PID value fluctuate when the following connectors are shaken? ―  A/F sensor ―  PCM	Yes	Repair or replace the applicable wiring harness or connector parts. Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.
		No	Replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-X 2.0].) Go to Troubleshooting Diagnostic Procedure to perform the repair completion verification.

Troubleshooting Diagnostic Procedure

―  Verify that the primary malfunction is resolved and there are no other malfunctions.

Step	Inspection	Results	Action
Repair completion verification 1	PURPOSE: 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. ―  Perform the KOER self test. (See DTC INSPECTION.) •  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].)
		No	Go to the next step.
Repair completion verification 2	PURPOSE: 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.
		No	DTC troubleshooting completed.