194002425 - H010 STEERING HARD / (STEERING IN BOTH DIRECTIONS)

There is a noticeable hardening in the steering (in both directions) with no assistance.The electric steering is known as MPU (motor pump unit) and is fitted directly on the steering box.The failure warning light should go off with the engine running.The MPU electric motor speed varies as the steering speed varies.
0PRELIMINARY CHECKSALL OKPROBLEMS ENCOUNTEREDACTION
Carry out a test steering fully in various conditions to check the actual onset of the hardening in both directions.Check:

  • Presence of oil in the reservoir
  • The oil level is between the minimum and the maximum
  • The battery is run down (not below 10.5 Volt)
  • The alternator is working properly
  • Connectors correctly connected at the MPU
    See E7045 ELECTRIC STEERING		Move on to Step 11. No oil in the MPU reservoir1.Add oil and bleed the system    Op. 0010T75 HYDRAULIC POWER STEERING SYSTEM BLEED AIR
2. Oil level not correct2.Restore correct oil level
3. Battery run down3.Charge battery
4. The alternator is not charging correctly4.Check/Replace the alternator, if defective
5. Connectors not correctly connected5.Restore the correct connections
1CHECK USING DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION
Connect the diagnostic equipment (Examiner or other instruments) to the electric steering node diagnostic socket and check:

  • for the presence of any errors
  • for the presence of any errors at the NBC
  • for the presence of any errors at the NCM
  • for the presence of any errors at the NAS
  • correct impedance of the CAN
  • presence of the SRS error at the system with ESP
Move on to Step 21. Errors present for the electric steering node1. Continue as described by the diagnostic equipment
2. CAN line from MPU to NBC faulty2. Restore CAN line electrical connections from MPU to NBC
3. CAN line from NCM to MPU faulty3. Restore CAN line electrical connections from NCM to MPU
4. CAN line from NGE to NAS4. Restore the CAN line electrical connections from the NGE to the NAS
5. Incorrect body proxy5. Replace Body computer with correct proxy
2STEERING ANGLE SIGNAL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Connect the Examiner to the ABS control unit and, in the parmeters ambient, check the operation of the steering angle signal by turning the steering wheel clockwise (to the right) where the values should decrease and turning it anti-clockwise they should increase.The value should be zero with the wheels perfectly straightMove on to Step 31. Value of parameter incorrect the vehicle has lost toe in1.Zero the parameter by regulating the steering rods and checking that the control unit is working properly by turning the steering wheel to the end of travel position in both directions
2. The steering wheel angle parameter value is always zero for the defective steering angle sensor2.Replace the steering angle sensor, (on the pinion for systems with ABS or located on the steering wheel for systems with ESP)
Cancel the errors, carry out a road test to ensure that the control unit checks whether the errors are still present,return to the workshop and check that the fault is no longer present using the diagnostic equipment.
3STEERING ANGLE SENSOR SUPPLY CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Using the Examiner in the Voltmeter function, check that the supply for the steering angle sensor in the steering box is correct    See Test 4110AB STEERING ANGLE SENSOR ON STEERING BOX CHECKMove on to Step 42.Sensor supply not correct1.Restore correct power supply.
2.Wiring between steering angle sensor and connector plate for the MPU broken/short circuited to earth2.Renew the correct wiring
3STEERING ANGLE SENSOR SUPPLY CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Using the Examiner in the Voltmeter function, check that the supply for the steering angle sensor on the steering wheel is correct    See Test 3350EB STEERING ANGLE SENSOR OPERATION CHECKMove on to Step 4Sensor supply not correctRestore correct power supply
4SPEED SIGNAL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Connect the EXaminer and check for the presence of the vehicle speed signalMove on to Step 5No speed signalRestore the speed signal for the ABS node
5CHECK USING DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION
Cancel the errors, disconnect the diagnostic station and place the key in the OFF position for about 10 secs.Start up the engine and turn the steering wheel to the end of travel position in both directions.Reconnect the Examiner diagnostic equipment and check that there are no errors at the electric steering control unitEnd of diagnosisThe fault persistsMove on to Step 6
6STEERING COLUMN CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Raise the vehicle at the front, check that the steering column rotates correctly by disconnecting it from the steering (take care not to rotate the steering column through more than 360° which could cause a loss of the reference position for the steering by the MPUMove on to Step 7Steering column hardness during rotationReplace the MPU    Op. 4130B25 POWER STEERING PUMP ASSEMBLY R R FOR VERSIONS WITH AIR CONDITIONER
7RACK AND PINION CLEARANCE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the pinion-rack clearance with the steering column detached and the wheels straightMove on to Step 8Pinion-rack clearance too largeReplace steering    Op. 4130A15 POWER STEERING BOX R R WITH FRONT SUSPENSION FRAME REMOVED
8BOOT CONDITION CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Remove the front wheels and the track rod ends from the hub.Check the condition of the boots.Move on to Step 9Boots brokenLubricate the steering and replace the bootsOp. 4120A30 LEFT OR RIGHT STEERING BOX BOOT (ONE) - REPLACE AT BENCH
9CHECK ON SLIDING AND FASTENING OF RACKALL OKPROBLEMS ENCOUNTEREDACTION
Check the sliding of the rackCheck the bush-rack radial clearanceCheck the fastening of the steering boxMove on to Step 101.Steering hardness1.Replace the steering    Op. 4130A15 POWER STEERING BOX R R WITH FRONT SUSPENSION FRAME REMOVED
2.Clearance too large2.Replace the steering    Op. 4130A15 POWER STEERING BOX R R WITH FRONT SUSPENSION FRAME REMOVED
3. Fastening loose3.Tighten the steering box fastening pins to torque.
10STEERING ROD JOINTS CLEARANCE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the clearance of the steering rod jointsMove on to Step 11Joints seized or with clearanceReplace the rods    Op. 4110B10 STEERING LINKS - R+R ON VEHICLE - CHECK TOE-IN/TOE-OUT SEPARATELY
11HARDENING/STICKING CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check that there is no hardening/sticking by rotating the hubsMove on to Step 12Clearance in the jointReplace the joint    Op. 4410B40 LOWER TRACK CONTROL ARM (WITH BALLJOINT) FOR LEFT OR RIGHT FRONT SUSPENSION (ONE) - R+R - CHECK WHEEL GEOMETRY SEPARATELY
12STEERING WHEEL RETURN CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Refit all the components detached: Test the vehicle and check that the steering wheel returns correctlyMove on to Step 13Steering wheel return poorRestore front wheel geometry    Op. 4450A10 FRONT WHEEL GEOMETRY - CHECK USING OPTICAL EQUIPMENT - INCLUDES ADJUSTMENT IF NECESSARY
13CHECK ON CORRECT OPERATIONALL OKPROBLEMS ENCOUNTEREDACTION
Check that the fault is no longer presentEnd of diagnosis