Overheat Message And Shift Strategy Changes (26/01/05/NAS)

Publication date: 2005-02-17
Reference number: 26/01/05/NAS

OVERHEAT MESSAGE AND SHIFT STRATEGY CHANGES

TECHNICAL SERVICE BULLETIN

Reference Number(s): 26/01/05/NAS, Date of Issue: February 17, 2005

LAND ROVER:	New Range Rover (LM)
ISSUE:	1
SECTION:	Cooling
AFFECTED VEHICLES:	New Range Rover (LM) 3A101029 onward

SITUATION:

BLOCKED COOLING CHANNELS CAUSE TRANSMISSION SHIFT CHANGES

The customer may experience high engine speeds associated with transmission shift pattern changes after driving for 25 minutes or longer. There may also be a transmission overheat message displayed on the instrument cluster. High transmission fluid temperatures may be the cause of the problem.

RESOLUTION:

CHECK COOLER FOR BLOCKAGE AND REPLACE IF INDICATED

There may be a partial blockage of the low flow circuits (lower eight tubes that supply coolant to the transmission cooler) in the coolant radiator. This can result in insufficient cooling of the automatic transmission fluid.

If the transmission fluid temperature exceeds a threshold value, the transmission control system will adopt a shift strategy intended to cool down the transmission. It achieves this by extending the shift points significantly. As a result, the transmission is inclined to change down to lower gears to keep the engine speed (and therefore the cooling) to its optimum.

Upon customer complaint of the above symptoms, follow the rectification procedure below to determine coolant flow rate from the radiator drain plug. A low flow will confirm partial blockage of the radiator. Replace the radiator if required.

PARTS INFORMATION:

PCC000850 - Radiator - Qty 1

DDW WARRANTY CLAIMS:

DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.

DDW WARRANTY CLAIMS

Description	SRO	Time (Hours)	Condition Code	Causal Part
Radiator blockage check	26.40.89/30	0.90	55	PCC000850
Radiator blockage check and replace the radiator	26.40.89/31	1.60	55	PCC000850

Normal warranty policy and procedures apply.

Material allowance is included in labor operation.

REPAIR PROCEDURE

TEST COOLANT FLOW RATE

Position the vehicle on a lift.
Set the heater controls to maximum.
NOTE: GTR lookup sequence is as follows:
GTR Home > NAS > Service Information/ LM New Range Rover/2005 > Workshop Manuals > Service Procedures > Bookmark "EXTERIOR FITTINGS/REPAIRS" > "Undertray - front" link
Refer to GTR Workshop Manual section 86.15.01 and disconnect the battery ground cable.
WARNING: Removing the filler cap from the coolant expansion tank while the system is hot could result in injury such as scalding caused by escaping steam or coolant.
Once the cooling system is sufficiently cool, remove the coolant expansion tank cap.
NOTE: GTR lookup sequence is as follows:
GTR Home > NAS > Service Information/ LM New Range Rover/2005 > Workshop Manuals > Service Procedures > Bookmark "CHARGING AND STARTING/REPAIRS" > "Battery" link
Refer to GTR Workshop Manual section 76.11.81 and remove the front vehicle undertray.
Clamp the lower sub cooler hose (Fig 1 ).

Fig 1: Clamping Lower Sub Cooler Hose

Install a tube to the drain tap and position a graduated measuring container beneath the radiator to collect coolant. (Fig 2 )

Fig 2: Positioning Graduated Measuring Container Under Radiator

CAUTION: Engine coolant will damage painted surfaces. If spilled, coolant must be immediately removed and the area cleaned with water.
NOTE:
For guidance purposes, representative times are listed to drain 250 ml (8.5 oz) from a new radiator and a blocked radiator:
- New radiator (zero blockage) -10 seconds
- Used radiator with confirmed blockage and exhibiting fault symptoms -1 minute 40 seconds
Using a stop watch, fully open the drain tap (Fig 3 ) and measure the time required to drain 250 ml (8.5 oz) of coolant.

Fig 3: Measuring Drain Rate

When 250 ml has been obtained, close the radiator drain tap.
NOTE: The time taken to drain 250 ml of coolant will indicate if there is a blockage within the low flow circuit of the radiator.
If there is no evidence of a blockage in the radiator based on the drain time, top up the coolant level and install the coolant expansion tank cap.
Perform additional diagnostics to determine the cause of the problem and perform associated repairs. Submit a separate Warranty Claim for these repairs.

REPLACED BLOCKED RADIATOR

NOTE: Where a blockage of the low flow circuit of the radiator is confirmed, the radiator MUST be replaced with a new unit. It is not possible to clear the blockage.

If blockage of the radiator is confirmed, refer to GTR Workshop Manual section 26.40.01 and remove the radiator.
Remove the clamp from the lower sub cooler hose (Fig 1 ).
CAUTION: Do not use water under high pressure to flush the system as it can damage coolant system components.
Flush cooling system with low pressure water source.
NOTE: GTR lookup sequence is as follows:
GTR Home > NAS > Service Information/ LM New Range Rover/2005 > Workshop Manuals Service Procedures > Bookmark "COOLING SYSTEM V8/REPAIRS" > "Radiator" link
Refer to GTR Workshop Manual section 26.40.01 and install a new radiator.
Fill and bleed the radiator with approved coolant mixture.
Connect T4 to the vehicle and load "Range Rover 14" or a later disc.
Begin a new diagnostic session.
Follow ALL on-screen instructions and perform the following steps:
- Select `Diagnostics'.
- Select `System Diagnostics'.
- Select `Automatic Transmission'.
- Select `Fault Code Diagnostics'.
- Clear fault codes.
- Return to System Diagnostics' screen.
- Select `Exterior Lights'.
- Select `Fault Code Diagnostics'.
- Clear fault codes.
End the diagnostic session and return to the 'Welcome' screen.
Disconnect T4 from the vehicle