B2CM39K1 - 406D9 4HP20 AUTOMATIC GEARBOX

REPAIR PROCEDURE / FAULT FINDING : GEARBOX

1 - REPAIR PROCEDURE

stage	condition / action in progress	comments
1	dialogue with the customer to be aware of the symptoms of malfunctioning	see stage 2
2	check that there is no exterior oil leak (risk of incorrect level)	anomaly(ies) : see stage 9 correct : see stage 3
3	check oil level and condition	anomaly(ies) : see stage 9 correct : see stage 4
4	read the fault codes global test	dialogue possible (yes) : see stage 5 / 6 dialogue possible (no) : see stage 10
5	presence of faults	see stage 9
6	no fault found	see stage 7
7	carry out a road test with the diagnostic equipment (parameter measurements)	incorrect value(s) (yes) : see stage 9 incorrect value(s) (no) : see stage 8
8	check correct	end of procedure
9	analysis of the results check faulty component(s) fill in and return the REPLACEMENT OR ASSISTANCE REQUEST form see SI no. 399	end of procedure
10	fill in and return the REPLACEMENT OR ASSISTANCE REQUEST form see SI no. 399	end of procedure

2 - DIALOGUE WITH THE CUSTOMER TO BE AWARE OF THE SYMPTOMS OF MALFUNCTIONING

Subject of the complaint .

Conditions in which the fault occurs (speed, load, selector position) .

Carry out a road test with the customer and note :

the manner in which the customer drives (nervously, very economically, clumsy movements...)
the external influences acting on the vehicle (temperature, road surface, use of electrical accessories)
programme in which the fault occurs (Sport, Snow, ECO)

3 - FAULT FINDING

Rapid diagnosis .

incident(s)	service action
the oil has a burnt smell	abnormal operation, even clutch damage, has resulted in overheating of the fluid which could be full of impurities with the engine running, take a small sample of fluid (approximately 0.2 litres) to detect the presence of a significant quantity of impurities (dust, particles of metal) if necessary, replace the gearbox
presence of water in the oil (emulsion)	check condition of the heat exchanger
oil level too low	check there are no oil leaks
vehicle goes forward or backward, selector in position (N) possible to start engine, selector in position (N) but not in (P)	adjust the selector control
engine can be started in all positions of the control selector	check : multi-function switch (see : Checks, Repairs Adjustments Brochure, (4HP20) automatic gearbox, diagnostics binder)
no vehicle drive, either forward or in reverse fluid level correct, the vehicle does not move, selector in position D - 3 - 2 - 1 fluid level correct, slip on starting, selector in position D, judder in reverse hot, no drive in any selector position, the vehicle restarts after a few minutes stopped	see Info Flash no. 399 (not issued in U.K.) (406 ) DIAG 2000
metallic noise at idle from the converter housing	check : tightening of the converter securing bolts condition of the converter drive plate (split)
noise on starting (starter action)	check : tightness of the plate on the torque converter condition of torque converter housing
squeaking from the oil pump gears	check the automatic gearbox oil level
dialogue not possible with diagnostic equipment	see : Checks, Repairs Adjustments Brochure, (1HP20) automatic gearbox, diagnostics binder 406
quality of gear changes reduced (no torque reduction)	see : Checks, Repairs Adjustments Brochure, (1HP20) automatic gearbox, diagnostics binder 406
flashing of the Sport and Snow warning lights, display of the last gear selected	mechanical fault in the automatic gearbox : check oil level and condition
flashing of the Sport and Snow warning lights (with no gear displayed)	see : Checks, Repairs Adjustments Brochure, (4HP20) automatic gearbox, diagnostics binder 406