3.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to " Power Circuit Inspection " procedure.
The computer has one of the management functions that is the voltage supply to the sensors.
The sensor supply votage 1 is fed to the APS 1 and MAFS to be used to operate the sensors.
If the signal is below threshold value, the ECM judged this as a fault and DTC is set.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Signal check, low | ● Open or short to ground in power circuit ● Faulty MAF or APS ● Faulty ECM |
Enable Conditions | ● Ignition on | |
Threshold Value | ● Output signal ＜ 4.7 V | |
Diagnostic Time | ● 0.1 sec. | |
MIL Fuel Limit Fuel Cut EGR Off | ● No ● Yes ● No ● No | |
Fail safe | ● Engine speed is fixed as 1200 rpm without the accel position sensor action. |
Sensor supply voltage 1 | |
Voltage | 4.8 ~ 5.1V |
Connect scantool to Data Link Cable (DLC).
Monitor " Accel Position Sensor and Mass Air Flow " parameter on the scantool.
Fig 1) Normal value with mass air flow and accel position sensor at idle.
Is the Current data displayed correctly ?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure .
▶ Go to "W/Harness Inspection" procedure.
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.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to " Power Circuit Inspection " procedure.
Ignition "OFF" & Engine "OFF".
Disconnect MAF and Acceleration pedal sensor connector.
Ignition "ON" & Engine "OFF".
Measure voltage between terminal 2 of the MAFS harness connector and chassis ground.
Measure voltage between terminal 5 of the APS1 harness connector and chassis ground.
Specification : Approx. 4.8 ~ 5.1V
Is the measured voltage within specifications ?
▶ Go to "Component Inspection" procedure.
▶ Check for open or short to ground in harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Ignition "OFF" & Engine "OFF".
Connect MAFS & Acceleration pedal sensor 1 connector.
Ignition " ON" & Engine "OFF".
Monitor that DTC P1522 is retrieved again after connecting MAFS & APS.
Is the DTC P1522 retrieved again ?
▶ Substitute with a known-good MAFS or/and APS and check for proper operation.
If the problem is corrected, replace MAFS or/and APS and then go to "Verification of Vehicle Repair" procedure
▶ Substitute with a known-good ECM and check for proper operation.
If the problem is corrected, replace ECM and then go to "Verification of Vehicle Repair" procedure
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode and then clear DTC.
Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
Go to the applicable troubleshooting procedure.
System is performing to specification at this time.
