Fault code 4281: Diagnosis/troubleshooting

DIAGNOSIS/TROUBLESHOOTING (FAULT CODE 4281)

Work instruction			Display OK	If not OK
1	Brake fluid	Checking the brake fluid level	OK Step 2	Correct the fluid level ->End
2	Check ground lead of the level switch	Ignition off Pull plug off brake fluid level switch Measure resistance between terminal 2 of plug on brake fluid level switch and ground	< 5 Step 3	Open circuit between terminal 2 of plug on brake fluid level switch and ground point 3 ->End
3	Check level switch	Measure resistance between terminal 1 of brake fluid level switch socket and terminal 2 of brake fluid level switch socket	approx. 100 (at 20 °C) Step 4	< 100 Short circuit in circuit between brake fluid level switch terminal 1 and brake fluid level switch terminal 2 Open circuit between brake fluid level switch terminal 1 and brake fluid level switch terminal 2 ->End
4	Check signal lead of the level switch	Pull off the PSM control module plug Measure resistance between PSM control module plug terminal 36 and brake fluid level switch terminal 1	< 5 Step 5	Open circuit between PSM control module plug terminal 36 and brake fluid level switch terminal 1 ->End
5	Check signal lead of the level switch for short circuit to B+	Pull off plug II on the instrument cluster Switch on ignition Measure voltage between PSM control module plug terminal 36 and ground	< 0.3V Step 6	Short circuit to B+ between PSM control module plug terminal 36 and brake fluid level switch terminal 1 and instrument cluster plug terminal II/4 ->End
6	Check signal lead of the level switch for short circuit to ground	Switch off ignition Measure resistance between PSM control module plug terminal 36 and ground	>500 Step 7	Short circuit to ground between PSM control module plug terminal 36 and brake fluid level switch terminal 1 and instrument cluster plug terminal II/4 ->End
7	PSM control module faulty		->End