P2172
P2172 - High Airflow-Vacuum Leak Detected, Instantaneous Accumulation
For wiring diagrams, refer to.
• When Monitored: Ignition on and engine running with no MAP sensor DTCs.
• Set Condition: The PCM detects that a large vacuum leak is present or that the signal voltage for both TP sensors is stuck at 2.5 volts and calculated MAP is less than the gas flow adaptation value. One trip fault will set within 5 seconds. ETC light will flash.
• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - Active DTC
• This fault code could be present if any Cam/Crank DTCs are set. No repair is necessary for P2172 if any Cam or Crank DTCs are set.
• Diagnose and repair any TP sensor or MAP sensor DTCs before continuing.
• Diagnose and repair any VSS or 5 volt supply circuit DTCs before continuing.
• The throttle plate and linkage should be free from binding and carbon build up.
• Make sure the throttle plate is at the idle position.
• With the scan tool, select view DTCs and review the DTC environmental information.
Is the good trip counter greater than 0?
Yes
• The DTC is not active at this time. Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC
No
• Go to Test Step 2 => [ Test
Step 2 - Vacuum Leak ]
Test Step 2 - Vacuum Leak
• This code is enabled to limit engine operation if a large vacuum leak should occur.
• A large vacuum leak is the most probable cause of this DTC.
• Inspect the intake manifold, power brake booster, and PCV system for any vacuum leaks.
• Inspect the throttle plate. If the throttle blade is bent or will not close, the throttle body may need to be replaced.
• Inspect the MAP sensor and throttle body for proper installation.
• Inspect the engine for any mechanical conditions that can cause improper engine vacuum.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 3 => [ Test
Step 3 - Map Sensor Operation ]
Test Step 3 - Map Sensor Operation
• Start the engine.
• With a scan tool, monitor the MAP sensor voltage.
• Snap the throttle.
Does the MAP sensor voltage vary from less than 2.0 volts at idle to more than 3.5 volts at wide open throttle?
Yes
• Go to Test Step 5 => [ Test
Step 5 - Throttle Follower Test ]
No
• Go to Test Step 4 => [ Test
Step 4 - MAP Sensor ]
Test Step 4 - MAP Sensor
• Turn the ignition OFF.
• Disconnect the MAP sensor harness connector.
• Disconnect the PCM harness connector.
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP sensor and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals.
• Check each of the MAP sensor circuits for high resistance or a shorted condition.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace the MAP sensor.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 5 - Throttle Follower Test
• Turn the ignition ON.
• With a scan tool, perform the throttle follower test and monitor the TP sensor 1 and TP sensor 2 voltages.
• Slowly press the throttle pedal down.
• The voltage for TP Sensor 1 should start at approximately 0.3 volts and increase to more than 4.7 volts.
• The voltage for TP Sensor 2 should start at approximately 4.7 volts and decrease to approximately 0.3 volts.
Is the voltage within the range specified for each sensor?
Yes
• Go to Test Step 7 => [ Test
Step 7 - PCM ]
No
• Go to Test Step 6 => [ Test
Step 6 - Throttle Body ]
Test Step 6 - Throttle Body
• Turn the ignition OFF.
• Disconnect the throttle body harness connector.
• Disconnect the PCM harness connector.
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the throttle body and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals.
• Check each of the throttle body circuits for high resistance or a shorted condition.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace the throttle body.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 7 - PCM
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP sensor and the PCM and between the throttle body and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals.
• Refer to any technical service bulletins that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace and program the PCM.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test