Dtc P2251[L3 With Tc] - Mazda CX-7 2007 Workshop Manual

DTC P2251[L3 WITH TC]

DTC P2251 Front HO2S negative current control circuit open
• The PCM monitors the front HO2S negative current control circuit voltage. If the voltage does not change
with the PCM control value while the engine is running, the PCM determines that the front HO2S negative
current control circuit is open.
Diagnostic support note
• This is a continuous monitor (HO2S).
DETECTION
• The MIL illuminates if the PCM detects the above malfunctioning condition in two consecutive drive cycles
CONDITION
or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
• PENDING CODE is available if the PCM detects the above malfunction conditions during the first drive
cycle.
• FREEZE FRAME DATA is available.
• DTCs are stored in the PCM memory.
• Front HO2S malfunction
• Connector or terminal malfunction
POSSIBLE
• Open circuit between PCM terminal 2AC and front HO2S terminal 1B
CAUSE
• Front HO2S heater cannot be controlled
• PCM malfunction
FRONT HO2S
FRONT HO2S
WIRING HARNESS-SIDE CONNECTOR
1C 1A
1D 1B
Diagnostic procedure
STEP
1 VERIFY FREEZE FRAME DATA AND
DIAGNOSTIC MONITORING TEST RESULTS
HAVE BEEN RECORDED
• Have the FREEZE FRAME DATA and
DIAGNOSTIC MONITORING TEST RESULTS
(HO2S related) been recorded?
2 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Verify related Service Bulletins and/or on-line
repair information availability.
• Is any related repair information available?
ON-BOARD DIAGNOSTIC [L3 WITH TC]
5
1C
7
5
1B
5
1A
2BE 2BA 2AW 2AS 2AO 2AK 2AG 2AC 2Y 2U 2Q 2M
2BF 2BB 2AX 2AT 2AP 2AL 2AH 2AD 2Z 2V 2R 2N
2C 2A
2D 2B
2BG 2BC 2AY 2AU 2AQ 2AM 2AI 2AE 2AA 2W 2S 2O
2BH 2BD 2AZ 2AV 2AR 2AN 2AJ 2AF 2AB 2X 2T 2P
INSPECTION
PCM
6
2Z
6
2AC
6
2AD
PCM
WIRING HARNESS-SIDE CONNECTOR
Yes Go to the next step.
No Record the FREEZE FRAME DATA and DIAGNOSTIC
MONITORING TEST RESULTS on the repair order, then
go to the next step.
Yes Perform the repair or diagnosis according to the available
repair information.
If the vehicle is not repaired, go to the next step.
No Go to the next step.
id010239813400
2I 2E 2A
2J 2F 2B
2K 2G 2C
2L 2H 2D
ACTION
01-02–241
01-02