Engine idle speed erratic

ENGINE IDLE SPEED ERRATIC

Model

Freelander 1.8 Petrol

Affected vehicles

All 1.8 petrol engine derivatives.

Date

1998-07-15

Reference

Bulletin 0007, CDS ref L8437bu

Bulletin text

Freelander 1.8 Petrol

AFFECTED RANGE:

All 1.8 petrol engine derivatives.

PROBLEM:

ENGINE IDLE SPEED ERRATIC

The customer complains of erratic behavior of the engine idle speed , for example, intermittent idle speed hang - up, engine slow to return to idle etc.

CAUSE:

• = Possible damage to the engine harness where the stepper motor wiring has chafed on the cylinder head (vehicles prior to VIN WA 606807).

• = Detection of a designed - in feature to damp engine ‘shunt’.

ACTION:

Where a customer complaint of erratic idle is received the vehicle should initially be assessed to confirm the presence of a problem.

A designed - in feature of MEMS idle speed control is a stepped return to idle to provide ‘throttle damping’.

This will be observed on the tachometer as the rpm ‘hanging’ for a few seconds while returning to idle.

The engine speed at which this occurs is variable depending on how high the engine speed is raised and how quickly the throttle pedal is moved.

If this condition is confirmed, advise the owner that this is a design feature and that no further action is required.

If an idle speed control problem is confirmed and the VIN is prior to WA 606807, it is possible that the wiring to the Idle Air Control Valve (IAC) stepper motor has been damaged by chafing on the cylinder head.

Examine the wiring to the IAC valve stepper motor, (refer to illustration 1 overleaf). If damage is confirmed, replace and secure the engine harness as described.

Bulletin N o : 0007 L8437bu 1 15.07.98

• = Secure the new wiring to the stepper motor housing using a suitable cable tie positioned as shown in 2, (refer to PARTS INFORMATION for cable tie details).

• = Cut off any excess length of cable tie when secured.

PARTS INFORMATION:

YSB105730 Engine harness - vehicles with air conditioning

YSB105740 Engine harness - vehicles without air conditioning

UKC6684L Cable tie - black 150mm long x 3,5mm wide

WARRANTY CLAIMS: Use Complaint Code: 7G0K

Use S.R.O.: 86.70.17 Time allowance: 1.50Hrs

• = Refer to Workshop Manual repair number 86.70.17 for engine harness replacement procedure.