SB-2013-04

SB-10052099-6700
CARS
Date: 30.04.2013
Model: Elise/Exige & Evora fitted with
Bosch ESP8 brake modules
Number: 2013/04
Copy files should be maintained by:
Service Manager
Service Reception
Supervisor
Parts Manager
TITLE:
Generation of C0460 Pressure sensor failure fault code.
REASON:
Instances of ABS (Anti-Lock Braking System) tell tale lamp illumination accompanied with fault code
C0460 (pressure sensor failure) have been reported back to Lotus Cars.
Although the pressure sensor located within the ABS module is non-serviceable; another potential
cause of this problem is the brake light switch plunger being incorrectly set.
The switch has 3 settings (as shown below), the correct setting of the brake light switch plunger results
in the switches internal contacts closing at the correct time in relation to the brake pedal travel exerted
by the driver.
Pedal effort/travel position		
No pedal effort - no pedal travel
Initial/light pedal effort - minor pedal travel
Light/moderate pedal effort - increased
pedal travel
Switch Stage
Off		
1st Stage
2nd Stage
Action
Cruise control available (if required).
Cruise control cancelled (if activated).
Brake lights illuminated coinciding with
an ABS module brake fluid line pressure
reading of between 2 - 6 Bar.
Incorrect setting of the switch plunger will result in the ABS brake line pressure being too high at the
time of brake light activation, thus generating a fault code and illuminating the ABS or Service tell tale
lamp.
ACTION:
In the event that any Lotus vehicle fitted with a Bosch ESP8 module displays fault code(s) C0460 or
P0571 (Cruise Control/Brake Switch A Circuit) when the ABS or Engine Management Systems are investigated using Lotus TechCentre, then the operation and setting of the brake light switch should be
checked in the first instance to eliminate it as a potential cause of failure before unnecessarily renewing
the ABS module or investigating other potential causes of cruise control failure.
Checking Switch operation
1.With TechCentre connected to the vehicle and
ignition on select ABS brakes>Live Data:
2.From the ‘Available Items’ table, select:
-- Brake light switch (03).
-- Brake switch.
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CARS
3.From within the driver’s footwell area, rotate the brake light switch
90° counter-clockwise within its mounting bracket and withdraw
(with the harness connector still attached to the switch).
4.Gently push the brake light switch plunger inwards towards the
housing until light resistance is met, select the ‘play’
option
from Lotus TechCentre and then gently release the plunger whilst
examining the readings shown on the live data screen.
If the switch is operating correctly then the TechCentre live data
readings should change in this order:
- Brake switch:
(1st stage) - Actuated
- Brake Light Switch (03): (2nd stage) - Actuated
Switch operation correct:
If moving the switch plunger produces the correct readings then it should be adjusted and refitted to the vehicle so it can be retested in situ,
see adjustment procedure below.
Switch operation incorrect:
If the correct readings cannot be displayed then the brake switch should be replaced, operation of the
new switch checked (as above) before adjusting and fitting on the vehicle.
Plunger adjustment
Reason:
The plunger uses an internal ratchet mechanism which can be adjusted to suit the vehicle allowing for
any brake pedal travel tolerance thus ensuring the correct phasing of the internal switch contacts in
relation to the switch plunger position and brake pedal position.
Procedure:
1.With the switch still removed from
the pedal box, push the plunger fully
inwards towards the switch housing
(light resistance will be felt until the
plunger overcomes its ratchet mechanism).
2.Pull the plunger outwards to its mid point
setting (approximately half way out from the
switch housing, 5 audible clicks should be
heard as it is being pulled) note, the plunger
is on a stiff ratchet mechanism which may
take some effort to extend.
Step 3. Brake
pedal depressed
whilst refitting
switch
Step 2. pull plunger
outwards to mid-way
position
Step 1. Push
plunger fully
inwards
3.Using your hand to push down on the brake pedal, refit the brake switch back into its pedal box
bracket.
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CARS
4.Gently release the brake pedal back to its normal position against
its bump-stop.
5.From the available items in Live Data, select ‘Pressure Sensor’ in
addition to the options already selected.
Step 4. Brake
pedal released
back against
bump stop
6.Select the ‘play’ option and gently depress and release the brake
pedal to simulate normal braking operations and examine the value
readings displayed on ABS live data in relation to:
- ‘Brake Switch’ (1st stage)
- ‘Brake Light Switch (03)’ (2nd stage)
- ‘Pressure Sensor’ (ABS brake line pressure).
Normal Values Proportional To Brake Pedal Depression
No pedal effort - no pedal travel
- ‘Brake Switch’ (1st stage)
No Actuation
- ‘Brake Light Switch (03)’ (2nd stage) 		
No Actuation
- ‘Pressure Sensor’ (ABS brake line pressure) + or - 0.5 Bar
Initial/light pedal effort - minor pedal travel
- ‘Brake Switch’ (1st stage)
- ‘Brake Light Switch (03)’ (2nd stage) 		
- ‘Pressure Sensor’ (ABS brake line pressure)
Actuated
No Actuation
+/- 0.5 Bar
Light/moderate pedal effort - increased pedal travel
- ‘Brake Switch’ (1st stage)
Actuated
- ‘Brake Light Switch (03)’ (2nd stage) 		
Actuated
- ‘Pressure Sensor’ (ABS brake line pressure) + 2 - 6 Bar
7.If the readings are not within range then remove the brake light switch again repeating step 2 of the
adjustment procedure but adjusting the plunger inwards or outwards against its ratched mechanism
as necessary until the correct readings are achieved.
8.Clear the fault code(s) and perform a vehicle road test to ensure the code(s) do not return
Note: Only if after performing this procedure the relevant tell tale light remains illuminated and the fault
code(s) return should other causes of failure be investigated.
CHARGES:
At time of bulletin publication, prior authorisation is required if carrying out this procedure on Exige S
(V6), please contact your nominated FSE (Field Service Engineer) or the Warranty Department for authority to submit a warranty claim.
If approved claims for 0.2 hr labour may be submitted quoting Operation Code 14.01.03 - 00, ‘A’ code
15, ‘B’ code 37. Please quote the fault code generated as well as the tell tale light illuminated in the
remarks column text.
Ends.