P2173-HIGH AIRFLOW/VACUUM LEAK DETECTED (SLOW ACCUMULATION)

For a complete wiring diagram Refer to Section 8W.

When Monitored:
Ignition on and engine running with no MAP Sensor DTCs.
Set Condition:
A large vacuum leak has been detected or 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 the code will set within 5 seconds. ETC light will flash.

Possible Causes

VACUUM LEAK

MAP SENSOR CIRCUIT(S) OPEN, SHORTED, OR HIGH RESISTANCE

THROTTLE POSITION SENSOR CIRCUIT(S) OPEN, SHORTED, OR HIGH RESISTANCE

MAP SENSOR

THROTTLE POSITION SENSOR

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Diagnostic Test

1. ACTIVE DTC

NOTE: Diagnose and repair any TP Sensor or MAP Sensor DTCs before continuing.

NOTE: Diagnose and repair any VSS or 5 Volt supply circuit DTCs before continuing.

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

NOTE: Make sure the throttle plate is at the idle position.

Start the engine and allow it to reach normal operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go to 2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2. VACUUM LEAK

NOTE: This code is enabled on engines equipped with a plastic intake manifold to limit engine operation if a large vacuum leak should occur.

NOTE: 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 low engine vacuum.

Were any problems found?

Yes

Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 3

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 below 2.0 volts at idle to above 3.5 volts at wide open throttle?

Yes

Go to 5

Go to 4

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 Powertrain Control Module (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 Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace the MAP Sensor.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

5. THROTTLE FOLLOWER TEST

Ignition on, engine not running.
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 0.5 volts and increase to approximately 3.3 volts.
The voltage for TP Sensor 2 should start at approximately 4.4 volts and decrease to approximately 1.7 volts.

Is the voltage within the range specified for each sensor?

Yes

Go to 7

Go to 6

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 Powertrain Control Module (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 Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace the Throttle Body in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

7. POWERTRAIN CONTROL MODULE (PCM)

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM) and between the MAP Sensor and the Powertrain Control Module (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 Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).