Test Procedure

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

KT1 DTC P0A05: VERIFY THE FAULT IS MECP RELATED

NOTE: The DTC P0A05 may be set as the result of the PCM taking a LOS action.

The PCM DTCs P1A0C, P1A0D, and P2105, or P1145 and P2279 present along with P0A05 indicate that actual fault is not MECP related.

Are the PCM DTCs P1A0C, P1A0D, and P2105, or P1145 and P2279 present during self-test?

Yes	No
DTC P0A05 was not set because of MECP related failure.	DTC P0A05 was set because of MECP related failure.
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .	GO to KT2.

KT2 DTC P0A05: VERIFY THAT THE HARD FAULT IS PRESENT

Is DTC P0A05 present in the KOEO or KOER self-test?

Yes	No
GO to KT3.	GO to KT9.

KT3 CHECK THE FUNCTIONALITY OF THE MECP CIRCUIT AT THE RELAY

Key in OFF position.
MECP Relay connector disconnected.

Connect a non-powered test lamp between:

( + ) Vehicle Battery	( - ) MECP Relay Connector, Harness Side
Positive terminal	MECPR - Pin 1

Key ON, engine OFF.
Access the PCM and control the MECP PID.
Cycle the MECP PID on and off.

Does the test lamp turn on and off when output state control is commanded on and off?

Yes	No
GO to KT4.	Key in OFF position. GO to KT6.

KT4 CHECK THE VPWR VOLTAGE TO THE MECP RELAY

Measure the voltage between:

( + ) MECP Relay Connector, Harness Side	( - ) Vehicle Battery
VPWR - Pin 2	Negative terminal

Is the voltage greater than 10.5 V?

Yes	No
Key in OFF position.	Key in OFF position. REPAIR the open circuit.
GO to KT5.	CHECK the condition of related fuses/fuse links. If damaged, CHECK the VPWR circuit for a short to ground.

KT5 CHECK THE MECP RELAY RESISTANCE

Measure the resistance between:

( + ) MECP Relay Connector, Component Side	( - ) MECP Relay Connector, Component Side
VPWR - Pin 2	MECPR - Pin 1

Is the resistance between 40 - 90 ohms?

Yes	No
Unable to duplicate or identify the fault at this time. GO to KT9.	INSTALL a new MECP relay.

KT6 CHECK THE MECP CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Key ON, engine OFF.

Measure the voltage between:

( + ) PCM Connector, Harness Side	( - ) Vehicle Battery
MECPR - Pin T4	Negative terminal

Is the voltage less than 1 V?

Yes	No
Key in OFF position. GO to KT7.	Key in OFF position. REPAIR the short circuit to PWR.

KT7 CHECK THE MECP CIRCUIT FOR AN OPEN IN THE HARNESS

PCM connector disconnected.

Measure the resistance between:

( + ) MECP Relay Connector, Harness Side	( - ) PCM Connector, Harness Side
MECPR - Pin 1	MECPR - Pin T4

Is the resistance less than 5 ohms?

Yes	No
GO to KT8.	REPAIR the open circuit.

KT8 CHECK THE MECP CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) Vehicle Battery
MECPR - Pin T4	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to KT10.	REPAIR the short circuit to GND.

KT9 CHECK THE MECP CIRCUIT FOR AN INTERMITTENT CONCERN

PCM connector connected.
MECP Relay connector connected.
Key ON, engine OFF.
Access the PCM and control the MECP PID.
Command the MECP ON.
Access the PCM and monitor the MECP_F PID.
Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.

Is a concern present during the wiggle test?

Yes	No
Key in OFF position.	Key in OFF position.
REPAIR as necessary.	GO to Pinpoint Test Z .

KT10 CHECK FOR CORRECT PCM OPERATION

Disconnect all the PCM connectors.
Visually inspect for:
- pushed out pins
- corrosion
Connect all the PCM connectors and make sure they seat correctly.
Carry out the PCM self-test and verify the concern is still present.

Is the concern still present?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.