P2175-LOW AIRFLOW/RESTRICTION DETECTED (SLOW ACCUMULATION)





For a complete wiring diagram Refer to Section 8W.



Possible Causes
RESTRICTED AIR INLET SYSTEM
RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT
(K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE TP SENSOR SIGNAL CIRCUIT
TP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K922) TP RETURN CIRCUIT
MAP SENSOR
TP SENSOR
PCM


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1. ACTIVE DTC

NOTE: The most likely cause of this DTC is a plugged intake air system or dirty Throttle Body. Check for any TSBs before continuing.

NOTE: Diagnose any 5-Volt Supply, TP Sensor, Oxygen Sensor, Fuel related or MAP Sensor DTCs 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 blade can cause this fault when ambient is around -10 to +4 degrees C (14 to 39.2 degrees F) range.


Ignition on, engine not running.
With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes


No

2. RESTRICTED AIR INLET SYSTEM

Turn the ignition off.
Remove the Air Cleaner Assembly.
Remove the Air Filter.
Inspect the Throttle Body opening for signs of any foreign materials.
Check the intake tube / air cleaner for obstructions - include snow packing questions to customer.

Were any restrictions found?

Yes


No

3. MAP SENSOR OPERATION

Start the engine.
With a scan tool, monitor the MAP Sensor voltage.
Snap the Accelerator pedal.

Does the MAP Sensor voltage vary from below 2.0 volts at idle to above 3.5 volts at Wide Open Throttle?

Yes


No

4. TP SENSOR OPERATION

Ignition on, engine not running.
With a scan tool, perform the Throttle Follower Test.
TP Sensor No.1 should start at approximately 0.8 of a volt and increase to 4.2 volts.
TP Sensor No.2 should start at approximately 4.2 volts and decrease to 0.8 of a volt.

Is the voltage transition smooth between the appropriate values?

Yes


No

5. RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT



Turn the ignition off.
Disconnect the Throttle Body harness connector.
Disconnect the C2 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.


Measure the resistance of the (F855) 5-volt Supply circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 100 ohms?

Yes


No

6. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and (F855) 5-volt Supply circuit at the Throttle Body harness connector.

Is the resistance above 100k ohms?

Yes


No

7. TP SENSOR





Connect the PCM harness connector.
Ignition on, engine not running.
With a scan tool, monitor the TP Sensor voltage.
Connect a jumper wire between the (K22) TP Signal 1 circuit and the (K922) TP Return circuit in the Throttle Body harness connector.
TP Sensor No.1 voltage should start at approximately 4.8 volts and decrease to 0.2 of a volt.
Connect a jumper wire between the (K122) TP Signal 2 circuit and the (F855) 5-volt Supply circuit in the Throttle Body harness connector.
TP Sensor No.2 voltage should start at approximately 0 volts and increase to 4.8 to 5.2 volts.

Does the TP Sensor voltage change to the appropriate voltage with the jumper wire installed?

Yes


No

8. RESISTANCE IN THE (K22) TP SIGNAL 1 CIRCUIT



Turn the ignition off.
Disconnect the C2 PCM harness connector.
Measure the resistance of the (K22) TP Signal 2 circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

9. RESISTANCE IN THE (K122) TP SIGNAL 2 CIRCUIT



Measure the resistance of the (K122) TP Signal 2 circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

10. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and the (K22) TP Signal 1 circuit at the Throttle Body harness connector.

Is the resistance above 100k ohms?

Yes


No

11. (K122) TP SIGNAL 2 CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and the (K122) TP Signal 2 circuit at the Throttle Body harness connector.

Is the resistance above 100k ohms?

Yes


No

12. RESISTANCE IN THE (K922) TP RETURN CIRCUIT



Measure the resistance of the (K922) TP Return circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

13. RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT



Turn the ignition off.
Disconnect the MAP Sensor harness connector.
Disconnect the C1 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.


Measure the resistance of the (F856) 5-volt Supply circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

14. (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and the (F856) 5-volt Supply circuit in the MAP Sensor harness connector.

Is the resistance above 100k ohms?

Yes


No

15. MAP SENSOR



Connect the C1 PCM harness connector.
Ignition on, engine not running.
With a scan tool, monitor the MAP Sensor voltage.
Connect a jumper wire between the (K1) MAP Signal circuit and the (K900) Sensor ground circuit.
Cycle the ignition switch from off to on.
With a scan tool, monitor the MAP Sensor voltage.

Does the scan tool display MAP voltage from approximately 4.9 volts to below 0.5 volt with the jumper wire installed?

Yes


No

16. RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT



Turn the ignition off.
Disconnect the C2 PCM harness connector.
Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

17. (K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.

Is the resistance above 100k ohms?

Yes


No

18. RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT



Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

19. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.


Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes


No