Tuesday, December 23, 2014

CONTROL ARM RUBBERS

VW POLO CONTROL ARM & TIE-RODS

A couple of weeks ago to my surprise,  I discovered that my car's front tyres were running  smooth on the inside.  It was that bad that I needed to replace them but somehow I never noticed until from a distance, I saw something white stuck to the right side front tyres. I was thinking it may be a sticky sweet wrapper that got stuck to the thread, so I went to remove it. That’s when I saw it was a patch of shining wire protruding through the rubber. I was dismayed. The outer edge up to the middle of the tyre had perfect thread, at least 4mm or more but the inside was bald as an egg. 


My VW Polo getting the full treatment.

Thats where the control arm rubbers sits, 

There was no way I was going to fit brand new tyres and allow the same to happen to them. I suspected that the alignment went awry so I drove my car in that condition to determine whether I was right or wrong. I released the steering on a straight road a few times and every time the car veered to the left, towards the pavement. Convinced that it was alignment, I fitted my spare wheel and took my VW Polo Highline for wheel alignment to get it sorted before replacing the tyres.

New VW control arm rubbers / cleaned-up VW control arms

Busted rubber boots on both and left tie-rod ends, due for replacement.

 After waiting for more than an hour at the wheel alignment centre, it was eventually my turn to get service. My car was hoisted about hip high on the lift. The technicians then jacked-up the front wheels placed metal pad of sorts under each of the front wheels which was part of the wheel alignment sensor equipment that they later fitted to all four wheels. They then centred the steering wheel, locked it in place with a mechanical device and fired up the diagnostic computer/programme to check my car's wheel alignment. A good 15 minutes later they discovered that their version of the diagnostic software did not have the settings for a VW Polo 2.0 litre Highline. In fact there wasn't even a 2.0 litre Polo category listed.

Front and back view of new tie-rod ends.

There is absolutely no difference between the original ans pirate part other than the VW logo

The technician scrolled through the entire list a couple of times before he gave up and told me that they are stuck without the correct setting and therefore cannot do the alignment. I asked, what about trying the software for one of the other VW Polo models. Considering all the Polo's are the same shape and size and that it’s only the engine capacity that vary, perhaps it may work.  So he tried the 1.8 litre setting which showed my Polo's alignment was perfect and that there was no error. He then tried the 1.6 and the 1.9TDi software, both with the same results -no problem. I protested “How can that be? Look at my front tyres! Now that the car's tyres were eye-level the left tyre was almost just as bad as the right one. The technicians agreed that there is a problem and started speculating that if both my swing arm rubbers were uniformly perished the alignment would  technically still be in but the car would veer off the road and the tyres would run bald on either the inner or outer edge. They lifted the car higher and pushed a tyre lever into the control arm rubbers and convincingly said the one side is definitely broken.  Thank you very much and off I went.


Left image shows left Control arm Rubber, Right image shows right side.

Left and Right Control Arm Rubbers

Back at the VW service agents, 2 x control arm rubbers please. Yes, we have stock, R1200 (+/-$120) please. What! For two pieces of rubber? But since I needed it, I paid. Back home I jacked-up the car, placed it on car stands and stripped the front suspension until I removed said rubbers. By the way, I found the boots on tie-rod ends torn so back to the agents I went. "Sorry out of stock, expecting stock to arrive in 40 days". This was unacceptable so off to the local motor spares I went in search of tie-rod ends. I found them sold together with the control arm rubbers at R180 each, tie-rod ends R120 each. Everything together cost me R600 ($60), exactly half of what I already spent on rubbers alone. So after I fitted them to my Polo, I returned the Control arm rubbers to the VW agents for a full refund.  Amazingly the car now drives normal, no veering to the left or right and the alignment centre still says my alignment is normal, even though they or none of the other service centres they phoned have the software alignment settings for my 2.0L Polo highline. I now realise that she's an oddball.


Tuesday, October 21, 2014

EPC DEMYSTIFIED CONTINUED 2

Continued from EPC DEMYSTIFIED CONTINUED 1.

  ...  I only became aware of this when my EPC light went on due to the knock sensor. See picture blog.  More...

 PART 3

BREAKING THE CODE
What needs to be mentioned as a basis of understanding, is that OBD (on-Board Diagnostics) was introduced in the 70's along with CDI (capacitive discharge ignition systems) as DIY kits. Few cars had fuel injectors, points and coils were fast being taken over by electronic modules. During this time some standards were introduced but they were not very well defined and as such manufacturers developed their own and applied their specific systems and developed their own code descriptions which later became known as OBD1. This was considered undesirable and counterproductive since none franchised service, and general mechanical repair centers had to purchase different scan tools, interface cables and connectors, skills and manuals for each make and model of car they specialized in. This resulted in vehicle diagnostics becoming unwieldy expensive. In February of 1986, Robert Bosch founder of Bosch, introduced the CAN (Controller Area Network) serial bus system to  the Society of Automotive  Engineers (SAE) in motor town of Detroit.

This influenced the  Society of Automotive  Engineers (SAE) who subsequently drafted a list of standards and practices that aught to be implemented by all automobile  manufacturers and recommended them to the Environmental Protection Agency (EPA). The EPA weighed-up these standards and recommendations, acknowledged their benefits, and adopted them. The standards criteria included a precisely defined diagnostic connector for each auto manufacturer, a standard scan tool and a common electrical communications protocol and a common data format, and the ability to monitor other
vehicle parameters. Lastly that the standard scan tool should interface with vehicles of all manufacturer. It also included mandatory definitions and descriptions for certain emission control system  defects which was labeled the ‘P0’ Codes. Manufacturers were allowed to generate and use their own ‘manufacturer specific code descriptions’ known as ‘P1’ Codes. This collaboration of standards became known as OBDII, (OBD2) and was adopted for implementation by January of 1996. Two types of scanner codes, namely manufacturers codes like VAG codes and SEA Codes are now the standard practice.

OBD-II  

As mentioned above, Powertrain Control Module (PCM) error codes are assigned the prefix P and pertain to the, Engine management, Transmission management, Fuel Pump and Gasoline Management, Automatic Transmission – Hydraulic Control, Emission control system, evaporative emission purge control (HVAC), Auxiliary module management and other some 0n-board Hybrid application.  For example P1340  suggests that the Powertrain triggered a DTC and describes it as an "Crankshaft-/Camshaft Position Sensor Signals Out of Sequence"

From the above example it would thus be easy to interpret the DTC below relating to EPC (Electronic Power Control)

DTC (VAG)   DTC (SAE)  Society of Automotive  Engineers

16504 P0120 Throttle Position Sensor A - Circuit Malfunction
16505 P0121 Throttle Position Sensor A - Circuit - Performance Problem - Out of Range
16506 P0122 Throttle Position Sensor A Circuit - Low Voltage Input
16507 P0123 Throttle Position Sensor A Circuit - High Voltage Input
16894 P0510 Throttle Position Sensor - Closed Switch- idle micro-switches -F60 malfunctioning
17951 P1543 Throttle Actuation Potentiometer - Signal too Low
17952 P1544 Throttle Actuation Potentiometer - Signal too High
17913 P1505 Throttle idle micro-switches -F60 not/short-circuit opens
17914 P1506 Throttle idle micro-switches - Switch Does Not Open/Short to Ground
17988 P1580 Throttle Actuator (B1) Fault - May be caused by low battery if found with 16487 (P0103)

18038 P1630 Accelerator Pedal Position -G79 signal too small  (low)
18039 P1631 Accelerator Pedal Position -G79 signal too largely (high)
18040 P1632 Accelerator Pedal Position -G79 supply voltage malfunction
18041 P1633 Accelerator Pedal Position -G185 signal too small
18042 P1634 Accelerator Pedal Position -G185 signal too largely
18047 P1639 Accelerator Pedal Position 1+2 Range/Performance -G79 and -G185 implausible signal
18048 P1640 Internal Controller Module defective (EEPROM) Error

EPC Circuit.

The EPC  circuit consists of a number of disparate components that control and supervise, regulate and determine the throttle valve position at all times. They include;

1) the accelerator pedal position sender (TP sensor G69)
2) the accelerator pedal position sender -2, (G185)
3) Black 6-pin plug with 6-pin with Gold plated contacts

NB! The above three components are part of the accelerator pedal.

4) the throttle valve control module (unit),
5) the K132 EPC fault lamp, (electronic throttle control fault indicator)
6) the engine control module (unit).

Firstly we going to do a test on components 1, 2 and 3 above. To do this test, you need a Fluke multimeter or similar for a voltage and continuity / resistance test. Unplug the 6-pin plug from the accelerator pedal and switch on the ignition. Connect the multimeter and check for a 4.5 volt reading between;-

pin 1 and ground, then between pin 1 and pin 5
Pin 2 and ground, then between pin 2 and 3.
If tests prove to be "OK", switch ignition off.
Do additional checks for short circuits between one another and ground and if this checks "OK",

Locate the ECU, normally inside cowl. Disconnect the ECU from its socket, identify pins 34 & 34, 35 & 36, and 72 & 73 on the socket. Disconnect the 6-pin plug from the accelerator pedal once again and check for continuity between this plug and the ECU socket. There should be continuity between pins:-

1 of the 6-pin plug and pin 72 of the ECU socket.
2 of the 6-pin plug and pin 73 of the ECU socket.
3 of the 6-pin plug and pin 36 of the ECU socket.
4 of the 6-pin plug and pin 35 of the ECU socket.
5 of the 6-pin plug and pin 33 of the ECU socket.
6 of the 6-pin plug and pin 34 of the ECU socket.

Any resistance above 1.5ohms should be investigated for corrosion. This often causes the engine to surge (idle unevenly or rather breaths) However, if this test proves "OK" and no wiring malfunction is detected, replace G69 and G185 (single unit) on the accelerator pedal. NB! these components are non adjustable and needs to be replaced as a whole.

When the ignition is turned on, the ECU checks all EPC components necessary for the proper  functioning of the Electronic Power Control. If a malfunction is detected in the EPC (Electronic Power Control) system whilst the engine is running, the ECM will simultaneously activate the EPC (Electronic Power Control) warning light and make an entry of this malfunction in  the ECU (electronic Control unit) DTC (Diagnostic Trouble Codes non-volatile memory.  By a process of eliminate the EPC fault can be fixed.

The list below categorises VW and Audi manufacturer predetermined data groups which varies depending on the vehicle, year, engine, engine code and management system on board.

Group Number / Group Category

1–9     General engine activity data
10–19 Ignition data
20–29 Knock control data
30–39 02 sensor control system data
40–49 Three-way CAT data
50–59 Engine speed control data
60–69 Throttle drive data
70–79 Emissions reduction data
80–89 Special function data
90–97 Power increase data
98–100 Compatibility data
101–109 Fuel Ignition data
110–119 Boost pressure control data
120–129 Control unit communication data
130–150 Special info data

Based on the data from the above table EPC problems are associated with group 60-69. However, on Expert Systems Diagnostics Group 60, holds the EPC Adaptation data, group 61 holds EPC-system 1 data and group 62 holds the EPC system 2 data. Group 66 holds the speed-o-cruise data.

NB! If you found this information useful, please link to this page.