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.

TR1 KOEO AND CONTINUOUS MEMORY DTC P1A0A: VERIFY THAT THE HARD FAULT IS PRESENT

NOTE: Clearing the TCM DTCs will erase any TCM recorded freeze frame data. Make sure to record any TCM freeze frame information before proceeding any further. Refer to the diagnostic tool instruction manual for freeze frame PID menu.

Clear and retrieve TCM continuous DTCs.

Is DTC P1A0A present?

Yes	No
GO to TR2.	GO to TR15.

TR2 CHECK THE IFS_PWR INPUT VOLTAGE TO THE TRACTION BATTERY

NOTE: Verify the front and rear inertia fuel shut off (IFS) switches are not tripped.

Key in OFF position.
TB-A connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

( + ) TB-A Connector, Harness Side	( - ) Vehicle Battery
IFS_PWR - Pin 23, 7	Negative terminal

Is the voltage greater than 10.5 V?

Yes	No
Key in OFF position.	Key in OFF position.
GO to TR4.	GO to TR3.

TR3 CHECK THE FRONT AND REAR IFS FOR AN OPEN

Disconnect the front and rear IFS switches.
Reset the front and rear inertia switches.
Measure the resistance across the normally closed contacts of the front and rear IFS switches.

Is each resistance less than 5 ohms?

Yes	No
Key in OFF position. IFS switch circuit failure. REPAIR as necessary. CHECK the condition of fuel fuse. If damaged, CHECK the VPWR circuit for a short to ground.	INSTALL a new IFS switch.

TR4 CHECK FOR AN IMMEDIATE SHUTDOWN REQUEST FROM TBCM

Key ON, engine OFF.
Access the TCM and monitor the I_SDN_1 and I_SDN_2 PIDs.

Do both I_SDN_1 and I_SDN_2 PIDs indicate discharge?

Yes	No
An open interlock circuit may be the cause for immediate shutdown. GO to HJ3 .	GO to TR5.

TR5 CHECK FOR ISDN1 SIGNAL LOW

NOTE: Use the PID reading from the PPT TR2.

Does only the I_SDN_1 PID indicate discharge?

Yes	No
Key in OFF position. GO to TR6.	GO to TR10.

TR6 CHECK THE ISDN1 CIRCUIT FOR AN OPEN IN THE HARNESS

Transaxle Assembly-A connector disconnected.

Measure the resistance between:

( + ) TB-A Connector, Harness Side	( - ) Transaxle Assembly-A Connector, Harness Side
ISDN1 - Pin 27	ISDN1 - Pin 6

Is the resistance less than 5 ohms?

Yes	No
GO to TR7.	REPAIR the open circuit.

TR7 CHECK THE ISDN1 CIRCUIT FOR A SHORT TO GROUND IN HARNESS

Measure the resistance between:

( + ) TB-A Connector, Harness Side	( - ) Vehicle Battery
ISDN1 - Pin 27	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to TR8.	REPAIR the short circuit to GND.

TR8 CHECK FOR THE ISDN1 CIRCUIT SHORTED TO CIRCUITS IN THE SAME HARNESS

Measure the resistance between:

( + ) Transaxle Assembly-A Connector, Harness Side	( - ) Transaxle Assembly-A Connector, Harness Side
ISDN1 - Pin 6	CAN+ - Pin 1
ISDN1 - Pin 6	CAN- - Pin 7
ISDN1 - Pin 6	B+ - Pin 12
ISDN1 - Pin 6	GND - Pin 2, 8
ISDN1 - Pin 6	PSR - Pin 4, 5

Are the resistances greater than 10K ohms?

Yes	No
GO to TR9.	REPAIR the short circuit.

TR9 SIMULATE ISDN1 NOT DISCHARGE SIGNAL TO THE TCM

TB-A connector connected.
Transaxle Assembly-A connector connected.
Isolate the ISDN1 circuit at the TB-A connector.

Connect a 5 amp fused jumper wire between the following:

Point A TB-A Connector, Harness Side	Point B Vehicle Battery
ISDN1 - Pin 27	Positive terminal

Key ON, engine OFF.
Access the TCM and monitor the I_SDN_1 PID.

Does the I_SDN_1 PID indicate discharge?

Yes	No
INSTALL a new transaxle assembly.	INSTALL a new traction battery.

TR10 CHECK FOR ISDN2 SIGNAL LOW

NOTE: Use the PID reading from the PPT TR2.

Does only the I_SDN_2 PID indicate discharge?

Yes	No
Key in OFF position.	Key in OFF position.
GO to TR11.	GO to TR15.

TR11 CHECK THE ISDN2 CIRCUIT FOR AN OPEN IN THE HARNESS

TB-A connector disconnected.
Transaxle Assembly-B connector disconnected.

Measure the resistance between:

( + ) TB-A Connector, Harness Side	( - ) Transaxle Assembly-B Connector, Harness Side
ISDN2 - Pin 13	ISDN2 - Pin 7

Is the resistance less than 5 ohms?

Yes	No
GO to TR12.	REPAIR the open circuit.

TR12 CHECK THE ISDN2 CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Measure the resistance between:

( + ) Transaxle Assembly-B Connector, Harness Side	( - ) Vehicle Battery
ISDN2 - Pin 7	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to TR13.	REPAIR the short circuit to GND.

TR13 CHECK FOR THE ISDN1 CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS

Measure the resistance between:

( + ) Transaxle Assembly-B Connector, Harness Side	( - ) Transaxle Assembly-B Connector, Harness Side
ISDN2 - Pin 7	CTO - Pin 1
ISDN2 - Pin 7	TGAC - Pin 9
ISDN2 - Pin 7	TMAC - Pin 4
ISDN2 - Pin 7	MSDN - Pin 5
ISDN2 - Pin 7	GSDN - Pin 10

Are the resistances greater than 10K ohms?

Yes	No
GO to TR14.	REPAIR the short circuit.

TR14 SIMULATE ISDN2 NOT DISCHARGE SIGNAL TO THE TCM

TB-A connector connected.
Transaxle Assembly-B connector connected.
Isolate the ISDN2 circuit at the TB-A connector.

Connect a 5 amp fused jumper wire between the following:

Point A TB-A Connector, Harness Side	Point B Vehicle Battery
ISDN2 - Pin 13	Positive terminal

Key ON, engine OFF.
Access the TCM and monitor the I_SDN_2 PID.

Does the I_SDN_2 PID indicate discharge?

Yes	No
INSTALL a new transaxle assembly.	INSTALL a new traction battery.

TR15 CHECK THE ISDN1 CIRCUIT FOR AN INTERMITTENT CONCERN

Key ON, engine OFF.
Access the TCM and monitor the I_SDN_1 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 TR16.

TR16 CHECK THE ISDN2 CIRCUIT FOR AN INTERMITTENT CONCERN

Key ON, engine OFF.
Access the TCM and monitor the I_SDN_2 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. REPAIR as necessary.	Key in OFF position. No fault found. The problem may be intermittent. GO to Pinpoint Test Z .