Operation CHARM: Car repair manuals for everyone.
Home >> Dodge or Ram Truck >> 2013 >> RAM 1500 Truck 2WD V8-5.7L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P2174

P2174






P2174-LOW AIRFLOW/RESTRICTION 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.

- 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 P2172, P2173. P2175.
- Set Condition:
The Powertrain Control Module (PCM) calculated MAP value is greater than actual MAP value plus an offset value. One trip fault. Three good trips to turn of the mil. 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 plugged intake air system or dirty Throttle Body. Check for any TSBs before continuing.

NOTE: Diagnose any 5-Volt Supply, TPS, Oxygen Sensor, Fuel related or MAP Sensor DTCs before continuing.

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 active DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

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

2. RESTRICTED AIR INLET SYSTEM
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. Check the intake tube and air cleaner for obstructions; include snow packing questions to customer.

Were any restrictions found?

Yes

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

No

- Go To 3

3. CHECK FOR EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT




1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the (F856) 5-Volt Supply circuit from the MAP Sensor harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the excessive resistance in the (F856) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. CHECK FOR EXCESSIVE RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT




1. Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

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

5. CHECK FOR EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT




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

Is the resistance below 5.0 Ohms?

Yes

- Go To 6

No

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

6. 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 7

No

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

7. THROTTLE POSITION SENSOR OPERATION
1. Ignition on, engine not running.
2. With a scan tool, perform the Throttle Follower Test.
3. TPS 1 should start at approximately 0.7 volts and increase to 4.3 volts.
4. TPS 2 should start at approximately 4.3 volts and decrease to 0.7 volts.

Is the voltage transition smooth between the appropriate values?

Yes

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

No

- Go To 8

8. CHECK FOR EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT




1. Turn the ignition off.
2. Disconnect the Throttle Body harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the (F855) 5-Volt Supply circuit from the Throttle Body harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 9

No

- Repair the excessive resistance in the (F855) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

9. CHECK FOR EXCESSIVE RESISTANCE IN THE (K22) TPS 1 SIGNAL CIRCUIT




1. Measure the resistance of the (K22) TPS 1 Signal circuit from the Throttle Body harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 10

No

- Repair the excessive resistance in the (K22) TPS 1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

10. CHECK FOR EXCESSIVE RESISTANCE IN THE (K122) TPS 2 SIGNAL CIRCUIT




1. Measure the resistance of the (K122) TPS Signal circuit from the Throttle Body harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 11

No

- Repair the excessive resistance in the (K122) TPS 2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

11. CHECK FOR EXCESSIVE RESISTANCE IN THE (K922) TPS SENSOR RETURN CIRCUIT




1. Measure the resistance of the (K922) TP Sensor Return circuit from the Throttle Body harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 12

No

- Repair the excessive resistance in the (K922) TPS Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

12. THROTTLE POSITION SENSOR
1. Connect the PCM harness connector.
2. Ignition on, engine not running.
3. With a scan tool, monitor the TPS voltage.
4. Connect a jumper between the (K22) TPS 1 Signal circuit and the (K922) TPS Return circuit at the Throttle Body harness connector.
5. TPS 1 voltage should start at approximately 4.7 volts and decrease to 0.3 volts.
6. Connect a jumper between the (K122) TPS 2 Signal circuit and the (F855) 5-Volt Supply circuit at the Throttle Body harness connector.
7. TPS 2 voltage should start at approximately 0.3 volts and increase to 4.7 volts.

Do the TPS voltages change to the appropriate voltage with the jumper installed?

Yes

- Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. Disconnect the Battery before replacing the Throttle Body Assembly. If OK, replace the Throttle Body Assembly. Throttle Body - Removal. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 13

13. 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.

pro multis · About Operation CHARM