Test Procedure

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

HG1 VISUAL INSPECTION OF PCV VALVE

NOTE: If PCV valve or tube is electrically heated, verify electrical connection. On some applications the vehicle may be equipped with a thermal harness that only provides electrical continuity when the temperature is less than 40°F (5°C) +/- 7°F (+/- 4°C). Typically this harness is located close to the PCV valve or tube.

NOTE: If the PCV valve is water heated, verify the coolant hose and clip connections.

CHECK the PCV valve, hoses and connections for leaks or restrictions.
Verify the PCV valve maintenance schedule has been followed.
Verify the proper PCV valve part number.
Verify the PCV valve is clean.
Verify the fresh air tube and related hoses are clean and routed correctly.

Is a concern present?

Yes	No
REPAIR as necessary. VERIFY the symptom no longer exists.	For electrically heated PCV tube, GO to HG3. For all others, GO to HG2.

HG2 STUCK PCV VALVE CHECK

Disconnect the PCV valve from the valve cover.
Shake the PCV valve.

Does the PCV valve rattle when shaken?

Yes	No
REINSTALL the PCV valve. For PCV systems with electrical heating, GO to HG3. For PCV systems without electrical heating, GO to HG11.	PCV valve is sticking. INSTALL a new PCV valve. VERIFY the symptom no longer exists.

HG3 CHECK FOR PCM CONTROLLED PCV HEATER

If thermal extension harness is present then PCV is non-PCM controlled. Refer to DESCRIPTION & OPERATION - GASOLINE MODELS .
CHECK if PCV heater is PCM controlled.

Is PCV heater PCM controlled?

Yes	No
GO to HG4.	GO to HG7.

HG4 CHECK HARNESS VOLTAGE TO PCM CONTROLLED PCV HEATER

PCV connector disconnected.
Key in ON position.

Measure the voltage between:

(+) PCV Connector, Harness Side	(-)
IGN START/RUN	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to HG5.	REPAIR the open circuit.

HG5 CHECK HARNESS CIRCUIT TO PCM CONTROLLED PCV HEATER

Key in OFF position.
PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCV Connector, Harness Side
PCVHC	PCVHC

Is the resistance less than 5 ohms?

Yes	No
GO to HG6.	REPAIR the open circuit.

HG6 CHECK THE RESISTANCE OF PCM CONTROLLED PCV VALVE OR TUBE HEATER

Measure the resistance between:

(+) PCV Connector, Component Side	(-) PCV Connector, Component Side
IGN START/RUN	GND

Is the resistance between 10 ohms - 35 ohms?

Yes	No
Key in OFF position. GO to HG13.	INSTALL a new PCV valve or tube.

HG7 CHECK POWER AND GROUND AT HARNESS ELECTRICALLY HEATED PCV VALVE OR TUBE NON-COMPUTER CONTROLLED

PCV connector disconnected.
PCVTE-Harness Side connector disconnected.

Measure the voltage between:

(+) PCVTE-Harness Side, Harness Side	(-) PCVTE-Harness Side, Harness Side
IGN START/RUN - Pin 1	GND - Pin 2

Is the voltage greater than 10.5 V?

Yes	No
Key in OFF position. For vehicles with thermal extension harness, GO to HG9. For all others, GO to HG10.	Key in OFF position. GO to HG8.

HG8 CHECK POWER CIRCUIT

PCV connector disconnected.
Key in ON position.

Measure the voltage between:

(+) PCV Connector, Harness Side	(-)
IGN START/RUN	Ground

Is the voltage greater than 10.5 V?

Yes	No
Key in OFF position. REPAIR open GND circuit.	Key in OFF position. REPAIR open PWR circuit

HG9 VALVE RESISTANCE CHECK WITHOUT EXTENSION HARNESS

Disconnect thermal extension harness from PCV valve.

Measure the resistance between:

(+) PCV Connector, Component Side	(-) PCV Connector, Component Side
IGN START/RUN	PCVHC

Is the resistance between 10 ohms - 35 ohms?

Yes	No
INSTALL a new thermal extension harness PCV.	INSTALL a new PCV.

HG10 CHECK THE RESISTANCE OF ELECTRICALLY HEATED PCV VALVE OR TUBE

Measure the resistance between:

(+) PCV Connector, Component Side	(-) PCV Connector, Component Side
IGN START/RUN	GND

Is the resistance between 10 ohms - 35 ohms?

Yes	No
Key in OFF position. GO to HG11.	INSTALL a new PCV valve or tube.

HG11 PCV SYSTEM CHECK

Start the engine and warm it until engine temperature is stable.
Disconnect the closure (fresh air) hose from the remote air cleaner or air outlet tube (the tube connecting the mass air flow sensor and the throttle body).
Place a stiff piece of paper over the hose end. Wait 1 minute.

Does vacuum hold the paper in place?

Yes	No
The PCV system is OK. Concern is elsewhere. RETURN to SYMPTOM CHARTS - GASOLINE MODELS for further direction.	System is leaking/plugged or Evaporative Emission system is leaking. GO to HG12.

HG12 EVAPORATIVE EMISSION SYSTEM CHECK

NOTE: If the evaporative emission hose is not connected to the PCV hose, follow the No Action to Take.

Disconnect the evaporative emission hose at the connection to the PCV hose (if equipped). Cap the connector.
Again place a stiff piece of paper over the closure (fresh air) hose end. Wait 1 minute.

Does vacuum hold the paper in place?

Yes	No
The PCV system is OK. REFER to EVAPORATIVE EMISSIONS to diagnose the evaporative emissions system.	CHECK for vacuum leaks/obstruction in the PCV system (such as oil cap, PCV valve, hoses, cut grommets, valve cover bolt torque/gasket leak). REFER to the VECI label for PCV system components and routing. REPAIR as necessary.

HG13 CHECK IF CONCERN OR DTC STILL PRESENT

Is the concern or DTC is still present?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	Unable to duplicate or identify the fault at this time. Concern is elsewhere. RETURN to SYMPTOM CHARTS - GASOLINE MODELS for further direction.