Code P1889

TSB
08-4-11 traction control lamp on - no dtcs present, or dtc p1889 in differential electronic module (dem).

Publication Date: February 14, 2008

FORD: 2005-2007 Five Hundred, Freestyle
MERCURY: 2005-2007 Montego

This article supersedes TSB 06-6-3 to update the symptom and the Service Procedure.

ISSUE:
Some 2005-2007 Five Hundred, Freestyle, and Montego vehicles equipped with All Wheel Drive (AWD) may exhibit the traction control warning lamp on. If the traction control lamp is on but no diagnostic trouble codes (DTCs) are retrieved, be sure to directly self test the DEM (4X4 module) using the diagnostic scan tool.

ACTION:
Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE:

Install the diagnostic scan tool and retrieve any available DTCs from the DEM, Anti-Lock Brake System (ABS) module and Instrument Cluster. If there are DTCs in the ABS module or instrument cluster, refer to Workshop Manual (WSM), Section 206-09 for ABS or WSM, Section 413-01 for instrument cluster for proper diagnostics. Do not continue with this TSB.

Note: Although the same warning lamp is shared for both systems, the dtcs for the awd and traction control system are not stored in the power-train control module (pcm) as on some other ford/mercury vehicles. The dem (4x4 module) must be selected, as it is an optional module only used on awd vehicles. Traction control dtcs are stored in the abs module. Vehicle wiring and communication dtcs related to the awd and traction control system are stored in the instrument cluster.

If DTC codes other than P1889 are present in the DEM, refer to WSM, Section 205-00 for additional diagnostic routines and do not follow this TSB procedure.
If DTC code P1889 is the only code present in the DEM, replace the oil pressure/temperature sensor (4B487) and clear the code. Refer to WSM, Section 205-02 under DEM In-Vehicle Repair.
NOTE: When replacing the oil pressure / temperature sensor, the o-ring seal (included in the kit) on the adjacent solenoid valve must also be replaced.

Note: The solenoid valve normally comes out of the on-demand coupling as the dem is removed. If it does not, either remove it by hand, or carefully remove it with pliers.

Remove the existing O-ring from the coupling body. (Figure 1)

Install the new O-ring included in the Pressure Sensor Kit, on the solenoid valve.

Install the solenoid valve and oil pressure/temperature sensor into the DEM (not into the coupling body) prior to assembling the DEM to the coupling body.
Note: Install the oil pressure / temperature sensor washer with the concave (dished) side facing the dem.

Perform a dynamic evaluation.
Start the engine and allow the vehicle to idle for a minimum of 5 minutes with the transmission in park.
Perform five (5) 0-25 MPH (0-40 Km/h) wide-open-throttle accelerations.

PART NUMBER PART NAME
7F9Z-4B487-A Pressure Sensor Kit

WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

OPERATION DESCRIPTION TIME
080411A 2005-2007 Five Hundred, Freestyle, Montego AWD Replace The Pressure Sensor Includes Time To Check DTCs And, Road Test (Do Not Use With 12650D, 12650DX1, 12651D, 12651DX1, 12651D4) 1.0 Hr.

NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge, tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do not assume that a condition described affects your car or truck. Contact a Ford, Lincoln, or Mercury dealership to determine whether the Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was current at the time of printing. Ford Motor Company reserves the right to supercede this information with updates. The most recent information is available through Ford Motor Company's on-line technical resources.

Make sure you have the new style seal. Check the picture above. Every one in the shop said it is very easy to over look.

Old seal is just an o-ring the new one should be different.
Check the picture above.

Then if all checking okay, next step is the pump.

Okay, as realworldfix says, try changing the fluid first. Then check the pump output pressure. If these are good (or done) and you still have the problem, then yes, you may have to replace the rear end.