Test Procedure

WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2004 Mercury Sable, 2004 Mercury Mountaineer, 2004 Mercury Monterey, 2004 Mercury Marauder, and 2004 Mercury Grand Marquis. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.

FAULT CODE SETTING CONDITION

Fault Code	KOEO	KOER	Continuous Memory
P0603	QB1
P1633	QB1	QB1	QB1

QB1 CHECK THE 12-VOLT BATTERY TERMINALS

NOTE: If KAPWR is interrupted to the PCM when a breakout box is installed or the battery is disconnected, DTC P0603/P1605 can be generated on the first power-up.

INSPECT the 12-volt battery cables for loose connections and for corrosion.

Are the 12-volt battery terminal connections in good condition?

Yes	No
KEY OFF GO to QB2.	Repair any concerns found.

QB2 INSPECT THE ENGINE COMPARTMENT FOR PROPER WIRE ROUTING

INSPECT the Electronic Engine Control (EC) system wiring for proper wire routing.
Check the wiring routing to establish if any of the electrical connectors are being stressed due to poorly routed wiring. If necessary re-route the wiring and secure.
Visually inspect wiring and connectors.

Are there any wiring problems?

Yes	No
Repair as necessary.	GO to QB3.

QB3 CHECK KEEP ALIVE POWER (KAPWR) TO THE PCM

PCM connector disconnected.

Measure the voltage between:

( + )PCM Connector, Harness Side	( - )12V vehicle battery
KAPWR	Negative terminal

While observing the multimeter, grasp the Electronic EC harness and wiggle, shake or bend a small section while working from the battery to the PCM.

Is the voltage less than 10.5 V?

Yes	No
ISOLATE the fault and REPAIR as necessary.	GO to QB4.

QB4 CHECK FOR A REPEAT OF THE DTC

PCM connector connected.
Clear all DTCs that may have been caused by the PCM disconnect.
Test drive the vehicle and allow the engine to reach normal operating temperature.
CHECK Self-Test DTCs:

Are DTCs P0603 or P1633 present?

Yes	No
INSTALL a new PCM REFER to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM	Unable to duplicate or identify the fault at this time REFER to POWERTRAIN DTC CHARTS & DESCRIPTIONS - CNG, FLEX-FUEL & GASOLINE , Diagnostic Trouble Code (DTC) Description for possible causes and additional DTC description information GO to Z1.