[Wilmo]

High Indicated Engine Temperatures / Perceived Overheating / Especially when towing and off road in sand

The 2005 CRDs came from the factory with an incorrectly calibrated temperature guage, which meant that the temp needle would sit near the HOT mark on the guage, even though the actual engine temperature was OK.

DC released a Technical Service Bulletin and upgraded software for Dealers to re-program the instrument cluster, so that it indicates only a minor increase in temperature rather than going to fully hot when the engine has been under load.

Details of the TSB are below - take this info to the Dealer and get them to re-program your KJ if you haven't had it done and are planning on towing or using the CRD off-road.

You will find however that the CRD KJ does indicate higher than normal temperatures (normal temp would be just under half indicated on the guage), when towing or fully loaded travelling at highway speeds, or off-road in deep sand. Under these conditions the turbo is generating a lot of heat! This scenario is not peculiar to the KJ either, the latest CRD Toyota Prado for example exhibits the same sort of behaviour when under high load - its normal for a turbo diesel.

Generally, you should aim to keep the temp below the 3/4 mark on the guage, and this is quite achievable, by moderating your speed on the highway. For example, in my experience, towing a 1 tonne trailer at 110km/h in 38 degree C temps produces temps around the 3/4 mark. Dropping speed to 100km/h sees the temperature fall a notch or two.

If after you have had the guage re-calibration done, and you are still getting temperatures in the red zone without much provocation, then its likely you have a faulty viscous clutch fan (the one on the front of the engine). This fan is only active at high engine temperatures, not all the time. If it doesn't engage, then overheating will occur. If you have a faulty one (its pretty rare), the dealer should replace it under warranty.

TSB

NUMBER: 08-043-05
GROUP: Electrical
DATE: August 11, 2005

THIS BULLETIN IS BEING PROVIDED IN ADVANCE. DO NOT PERFORM ANY
ACTIONS RELATED TO THIS BULLETIN UNTIL AUGUST 26, 2005. THE DRB III
SOFTWARE VERSION MUST BE AT LEVEL 62.2 TO PERFORM THIS BULLETIN. THE
DRB III SOFTWARE WILL BE AVAILABLE ON TechCONNECT BY AUGUST 26, 2005.
FOR MARKETS OUTSIDE OF THE UNITED STATES AND CANADA, THE DRB III
VERSION 62.2 SOFTWARE WILL BE AVAILABLE ON CINONConnect AND
TechCONNECT BY AUGUST 26, 2005. THE DRB III VERSION 62.2 SOFTWARE WILL
ALSO BE AVAILABLE ON THE ITIS DVD SEPTEMBER 2005 RELEASE.

SUBJECT:
Engine Temperature Gauge - Indicator Reads A Higher Temperature Than Actual

OVERVIEW:
This bulletin involves reprogramming the instrument cluster control (CCN)
module.

MODELS:
2005 (KJ) Liberty / Cherokee

NOTE: This bulletin applies to vehicles equipped with a 2.8L turbo diesel
engine (sales code ENR).

SYMPTOM/CONDITION:
The customer may notice that the engine temperature gauge may indicate that
the engine temperature is high. In hot ambient temperatures, and under certain driving
conditions of extended uphill driving while towing a trailer, the engine temperature
indicator may indicate slightly above the 3/4 normal operating temperature mark on the temperature gauge (but below the engine hot temperature markings). This condition may be caused by an incorrect calibration of the of the engine temperature gauge.

New CCN module software corrects the old engine temperature gauge
calibration.

DIAGNOSIS:
If the engine and the cooling system are operating correctly, and the above
condition is present, then perform the Repair Procedure.

SPECIAL TOOLS/EQUIPMENT REQUIRED:
CH6000A Scan Tool (DRBIII®)
NUMBER: 08-043-05
GROUP: Electrical
DATE: August 11, 2005
CH7000A/7001A J1962 Cable with red DRBIII® connector
REPAIR PROCEDURE:
NOTE: Before proceeding verify that the DRBIII® software version is at level 62.2.
1. Connect the DRBIII® to the vehicle Data Link Connector (DLC)
2. Turn the ignition switch to the "ON" position.
3. Using the DRBIII® scan tool recalibrate the instrument temperature gauge.
a. Select "DRBIII® Standalone"
b. Select "1998 - 2006 Diagnostics"
c. Select "All (Except Below)"
d. Select "Body Interior"
e. Select "Electro/Mech Cluster (MIC)"
f. Select "Miscellaneous"
g. Select "Recalibrate Temp Gauge" option.
4. If the recalibration of the instrument cluster was successful, the DRBIII® will display the following message: "Recalibration Successful".
5. If the version level of the original instrument cluster software allows recalibration, but the recalibration of the instrument cluster was NOT successful, then the DRBIII® will display one of the following messages: "Recalibration Failed" or "Write To Memory Address Failed". If one of these messages occurs repeat the above steps.
6. If the instrument cluster has already been recalibrated to the correct software version level, then the DRBIII® will display the following message: "Gauge Already Recalibrated - Press Any Key to Exit".
7. The DRBIII® will display the following message if the original instrument cluster software version level is not the correct version level for recalibration:
"MIC Software Version Incorrect - Press Any Key to Exit".
8. Verify that the instrument cluster engine temperature gauge has been recalibrated by selecting the "Recalibrate Temp Gauge" option again. The DRBIII® should display the following message: "Gauge Already Recalibrated - Press Any Key to Exit".
9. Turn the vehicle ignition switch to the "OFF" position
10. Disconnect the DRBIII® from the vehicle DLC.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation
No:
Description Amount
08-45-10-94 Reprogram Instrument Cluster Control (CCN)
Module - 2.8L Turbo Diesel Engine Only
0.2 Hrs.
FAILURE CODE:
AM Authorized Modification