P2172

P2172-HIGH AIRFLOW/VACUUM LEAK DETECTED (INSTANTANEOUS ACCUMULATION)

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Electronic Throttle Control (ETC) Motor is controlled by the Powertrain Control Module (PCM). The DC motor located in the throttle body drives the throttle blade. In order to decrease idle speed, along with spark and fuel delivery changes the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate.

- When Monitored:
With the engine running above 285 RPM and none of the following DTCs active; (TPS DTCs) P0121, P0122, P0123, P0221, P0222, P0223, P2135, (MAP DTCs) P0107, P0108, P0129, (5-Volt Supply DTCs) P0642, P0643, P0652, P0653, P1618, P1628, (CKP and CMP) P0016, P0335, P0339, P0340, P0344, and P2173, P2174. P2175.

- Set Condition:
A large vacuum leak has been detected based on the calculated MAP value minus the actual MAP is greater than 40kpa (5.8 psi) for 0.28 seconds. One trip fault. ETC light will flash.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC

NOTE: The most likely cause of this DTC is a vacuum leak. Check for any TSBs before continuing.

NOTE: The throttle plate should be free from binding and carbon build up.

NOTE: Question the customer about weather conditions, as ice build up on the throttle blade can cause this fault when the ambient air temperature is in the -10°C (14°F) to 4°C (39°F) range.

1. Turn the ignition on.
2. With the scan tool, record and erase all DTCs.
3. Start the engine and allow it to idle.
4. With a scan tool, read the active DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. VACUUM LEAK INSPECTION
1. Turn the ignition off.
2. Remove the Air Cleaner Assembly.
3. Remove the Air Filter.
4. Inspect the Throttle Body opening for signs of any foreign materials or excessive carbon build up.
5. Thoroughly inspect the engine area for any vacuum leaks.

Were any leaks found?

Yes

- Repair the leaks as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT




1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Disconnect the C2 PCM harness connector.
4. Measure the resistance of the (K1) MAP Signal circuit between the MAP Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the excessive resistance in the (K1) MAP Signal circuit
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT




1. Measure the resistance of the (K900) Sensor ground circuit between the MAP Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the excessive resistance in the (K900) Sensor ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. MAP SENSOR OPERATION
1. Reconnect the MAP Sensor and PCM C2 harness connectors.
2. Perform the CHECKING THE MAP SENSOR OPERATION test procedure Checking The MAP Sensor Operation .

Is the MAP Sensor operating properly?

Yes

- Go To 6

No

- Replace the MAP Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor, Throttle Body, and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the MAP Sensor, Throttle Body, and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.