DTC P0720, P0721, P0722[LA4AX-EL (CD4E)]

id050207806300

DTC P0720

Output shaft speed (OSS) sensor malfunction

DTC P0721

Output shaft speed (OSS) sensor signal noise

DTC P0722

Output shaft speed (OSS) sensor intermittent signal input
DETECTION CONDITION
•  P0720: PCM detects that insufficient OSS sensor signal while driving
•  P0721: PCM detects noise from OSS sensor signal while driving
•  P0722: PCM detects intermittent OSS sensor signal input while driving
POSSIBLE CAUSE
•  OSS sensor malfunction.
•  Short to ground in wiring harness between OSS sensor terminal A (wiring harness-side) and PCM terminal 84 (wiring harness-side).
•  Short to power supply in wiring harness between OSS sensor terminal A (wiring harness-side) and PCM terminal 84 (wiring harness-side).
•  Short to power supply in wiring harness between OSS sensor terminal B (wiring harness-side) and PCM terminal 3 (wiring harness-side).
•  Open circuit in wiring harness between OSS sensor terminal A (wiring harness-side) and PCM terminal 84 (wiring harness-side).
•  Open circuit in wiring harness between OSS sensor terminal B (wiring harness-side) and body ground.
•  Damaged connectors between OSS sensor and PCM.
•  PCM malfunction.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has the FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT OSS SENSOR CONNECTOR FOR POOR CONNECTION
•  Turn the ignition switch to the LOCK position.
•  Disconnect the OSS sensor connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion)
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace connector and/or terminal, then go to Step 9.
4
INSPECT OSS SENSOR CIRCUIT FOR SHORT TO GROUND
•  Inspect for continuity between OSS sensor connector A (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Repair or replace the wiring harness, then go to Step 9.
No
Go to the next step.
5
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminals, then go to Step 9.
6
INSPECT OSS SENSOR CIRCUIT FOR OPEN CIRCUIT
•  Inspect the following OSS sensor terminals (wiring harness-side) and PCM terminals (wiring harness-side):
―  A and 84
―  B and 3
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 9.
7
INSPECT OSS SENSOR CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the ignition switch to the ON position (engine off).
•  Inspect the voltage at OSS sensor terminals A and B (wiring harness-side).
•  Is the voltage 0 V?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 9.
8
INSPECT OSS SENSOR
•  Inspect the OSS sensor.
•  Is OSS sensor normal?
Yes
Go to the next step.
No
Replace the OSS sensor, then go to the next step.
(See OUTPUT SHAFT SPEED (OSS) SENSOR REMOVAL[LA4AX-EL (CD4E)].)
(See OUTPUT SHAFT SPEED (OSS) SENSOR INSTALLATION[LA4AX-EL (CD4E)].)
9
VERIFY TROUBLESHOOTING OF DTC P0720 P0721 OR P0722 COMPLETED
•  Make sure to reconnect all the disconnected connectors.
•  Clear the DTC from memory using the M-MDS.
•  Perform the “After Repair Procedure”.
•  Are any DTCs present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)
No
Go to the next step.
10
VERIFY DTCS
•  Are except DTC P0720, P0721 and P0722 output?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE[LA4AX-EL (CD4E)].)
No
DTC troubleshooting completed.