P1308
DTC P1308 ACCELERATION SENSOR CIRCUIT LOW INPUTComponent Location:
GENERAL DESCRIPTION
The Chassis acceleration(Rough Road) sensor consists of a piezoelectric vibration pick up which detects vertical acceleration of the vehicle.The sensor signal is used by the PCM to determine the degree et vertical movement of the car, for example, on a bumpy road. Since this may also cause uneven engine running, the PCM usee the signal to distinguish the phenomenon from actual misfiring.
DTC DESCRIPTION
PCM sets a DTC P1308 when signal output is lower than predetermined value.
DTC Detecting Condition:
Specification:
Schematic Diagram:
WAVEFORM INSPECTION
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
1. Engine "ON"
2. Monitor wave form at the terminal 3 of Acceleration sensor.
Specification
While Idle 2.3 - 2.7 V
OFF :0 V
3. Is parameter displayed within specifications?
YES: Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection1 bending, corrosion, contamination,deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO: Go to "W/Harness Inspection" procedure.
TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES: Repair as necessary and go to "Verification of vehicle Repair" procedure.
NO: Go to "Power Circuit inspection" procedure.
POWER CIRCUIT INSPECTION
1. Ignition "OFF"
2. Disconnect Acceleration sensor connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 1 of sensor harness connector and chassis ground.
Specification : approximately 5 V
5. Is measure voltage within Specification?
YES: Go to "Signal circuit inspection" procedure.
NO:
- Short circuit to chassis ground between Acceleration sensor harness connector and reference voltage.
- Open circuit between Acceleration sensor harness connector and PCM connector.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NOTE: In case, when acceleration sensor connector is disconnected, the voltage at terminal 1 is 0 V
- Possible cause: Open or short circuit in harness between terminal 32 of PCM and terminal 1 of acceleration sensor or PCM
SIGNAL CIRCUIT INSPECTION
1. Check for short to ground in harness
1. Ignition "OFF"
2. Disconnect Acceleration sensor connector and PCM connector.
3. Ignition "ON" & Engine "OFF"
4. Measure resistance between terminal 2 and 3 of sensor harness connector.
Specification: infinite
5. Is measure resistance within Specification?
YES: Substitute with a know-good Acceleration sensor and check for proper operation. If the problem is correct fed, replace Acceleration sensor and then go to "Verification of Vehicle Repair" procedure.
NO:
- Open circuit or short circuit to chassis ground between Acceleration sensor harness connector and signal circuit.
- Open circuit between Acceleration sensor harness connector and PCM harness connector.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NOTE: In case,when acceleration sensor connector is disconnected,the voltage at terminal 3 is 0 V.
- Possible cause: Open or short circuit in harness between terminal 80 of PCM and terminal 3 of acceleration sensor or PCM
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all rediness test have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.