V6 problems after cam cover gasket change

[Joner1983]

Hi everyone. I haven't posted on here for a very long time but I'm in need of some help.
Today I've changed my spark plugs and cam cover gaskets on my 1994 Cav v6 and since I've done that I now have engine management light on, TC light on and my idle is irregular. Everything went back together as it came off and I'm struggling to figure out whst I've done wrong.
Any help is gratefully received.

Cheers, Joner

[Cavalier342]

The V6s have a ton of vacuum breather hoses, and electronic plugs, just take your time and inspect them all again to make sure that plugs are tightly secure and the breather hoses are correctly fitted, some of them are next to others so always possible to cross them over by mistake. Sounds like it could be a throttle position sensor plug loose or something silly like that, it's just not getting the signal so throwing up fault lights. If I remember right, the traction control system is built into the throttle body, so definitely double check the plugs and wiring around that area.

[Joner1983]

Cheers Cavalier342, I'll have another look and a fiddle with the plugs. I drove it 30 miles home and it drove fine apart from it stalling at the lights so can't be too much wrong....

[Cavalier342]

No worries, keep us posted.

[Robsey]

Quick question...
Have you done the paper-clip tests for the engine ecu and for the traction control module?

If both lights are on, then fault codes will be stored for any issues relating to them.

[Joner1983]

Hi Robsey. Nah, I haven't tried that yet. Any idea where the plug is located on a v6 to do the paperclip test?

[Robsey]

If it is the same as all other Cavaliers, it will be in the back corner of the engine bay, tucked up behind the supplementary fuse box and alarm sounder.

Try a look at the TopBuzz website.
All the information you could need is there.
http://www.topbuzz.co.uk

Look in the technical section. (Info Tech).

[Joner1983]

Nice one, I'll have a look at doing that tomorrow. Cheers

[Robsey]

Here is a write up of the Traction Control test procedure from my other forum.

ALDL 10-Pin Diagnostics - TC (Traction Control) and 4X4

(Courtesy of Andy Kirwan's Technical site - updated and edited)

To diagnose faults on the 4X4 or TC systems, it is necessary to short Pin J to Pin A on the diagnostic plug.  Turn the ignition on, engine not running.

The relevant Tell-tale light on the instrument cluster should flash out the fault codes
 
Traction Control  Short pins A and J on the diagnostic plug

14 Coolant temperature sensor - voltage low    (20XE only)              
15 Coolant temperature sensor - voltage high   (20XE only)
21 Throttle position sensor - voltage high   (20XE only)                  
22 Throttle position sensor - voltage low    (20XE only)
26 Traction control Throttle position sensor - voltage high
27 Traction control Throttle position sensor - voltage low
31 No Engine RPM Signal
37 Stop Lamp Switch ( Pedal Switch )
39 LH Front Speed Sensor 
42 RH Front Speed Sensor 
44 LH Rear Speed Sensor 
46 RH Rear Speed Sensor 
55 ECU fault
57 ABS status signal low  (ABS light on indicating fault with ABS system, fix this ABS fault first)
58 ABS status signal open circuit
63 Throttle motor (ETC) motor open circuit
64 Throttle motor (ETC) motor short circuit
82 On/Off switch voltage low.

A common problem is the traction control motor plug being damp.

The TC coolant temperature sensor is located in the engine ecu coolant temperature sensor on the 20XE M2.5. 
If this is found to be faulty is should be replaced with the correct sensor. ie a black one not a blue one.


Fault codes 39, 42 ,44 ,46 and 57 are faults with the ABS system not the traction control system and therefore the ABS light should be on. Fix the ABS fault and the traction control fault code should go away.

In the unlikly event no ABS fault can be found check the following wires that run between the ABS and TC ECU 

Blue, Blue/green, Blue/white, Blue/red, Brown/yellow.    Listed in order of fault code numbers.

[Robsey]

Engine ECU test procedure.

To get the flash code, you need to short pin A to pin B of the diagnostic socket.
Turn on the ignition, with the engine NOT running.
The Engine Management Light (EML or MIL) will flash each fault code three times, starting with 

  1 - 2,  1 - 2, 1 - 2 and so on
When you get past the LAST fault code, it will go back to the start (  1 - 2,  1 - 2, 1 - 2 )

12 Diagnosis initiation/separator (indicates beginning/end of fault code list)
13 Oxygen sensor - open circuit
14 Coolant temperature sensor - voltage low
15 Coolant temperature sensor - voltage high
16 Knock signal circuit - no voltage change
17 Knock signal circuit 2 - no voltage change (V6 models only)
18 Knock control module (ECU)
19 Incorrect RPM signal (Crankshaft sensor - incorrect signal)
21 Throttle position sensor - voltage high
22 Throttle position sensor - voltage low
23 Knock sensor - out of range
24 Speed sensor (MPH)
25 Injector 1 - voltage high
26 Injector 2 - voltage high
27 Injector 3 - voltage high
28 Injector 4 - voltage high
29 Injector 5 - voltage high/ Fuel pump relay voltage low (non-V6 models)
30 Injector 6 - voltage high (V6 models only)
31 No engine RPM signal (engine not running, or no Crankshaft sensor signal)
32 Fuel pump relay - voltage high
33 MAP sensor - voltage high
34 MAP sensor - voltage low
35 Idle air control valve stepper motor (no idle speed control)
38 Oxygen sensor - voltage low (weak mixture)
39 Oxygen sensor - voltage high (rich mixture)
41 1 gear indent switch - voltage low
42 1 gear indent switch - voltage high
43 EGR system
44 Oxygen circuit - voltage low (weak mixture)
45 Oxygen circuit - voltage high (rich mixture)
47 Linear EGR position
48 Battery - voltage low
49 Battery - voltage high
51 ECU memory failure
52 Check engine light - voltage high
53 Fuel pump relay - voltage low
54 Fuel pump relay - voltage high
55 ECU faulty
56 Idle air control valve - voltage low/high
57 Idle air control valve - voltage high/low
61 Fuel tank vent valve - voltage low
62 Fuel tank vent valve - voltage high
63 EST line coil cylinders 2 & 3 - voltage low
64 EST line coil cylinders 1 & 4 - voltage low
65 Idle CO potentiometer - voltage low
66 Idle CO potentiometer - voltage high
67 Idle position switch - voltage low (idle position switch not opening)
69 Intake air temperature sensor - voltage low
71 Intake air temperature sensor - voltage high
72 Full position switch - voltage high
73 Air flow sensor - voltage low
74 Air flow sensor -voltage high
75 Torque control - voltage low
76 Torque control - continuous
79 Full load inhibitor - voltage low (traction control signal)
81 Injector valve 1 - voltage low
82 Injector valve 2 - voltage low
83 Injector valve 3 - voltage low
84 Injector valve 4 - voltage low
85 Injector valve 5 - voltage low (V6 models only)
86 Injector valve 6 - voltage low (V6 models only)
87 A/C cut-off relay - voltage low
88 A/C cut-off relay - voltage high
92 Camshaft sensor failure
93 Hall sensor - voltage low
94 Hall sensor - voltage high
95 Hot start valve - voltage low
96 Hot start valve - voltage high
97 Ignition/Injection cut off - voltage high (traction control signal)
113 Boost control out of range (turbo models only)
114 Boost pressure (idle) above upper limit (turbo models only)
115 Boost pressure (full) below upper limit (turbo models only)
116 Boost pressure (full above upper limit (turbo models only)
117 Wastegate valve - voltage low (turbo models only)
118 Wastegate valve - voltage high (turbo models only) 

[Joner1983]

Had a poke around tonight and it seems like the problem was the plug for the sensor on the side of the throttle body wasn't push in quite enouth. Started it up after and EML and TC light both went out. I feel rather foolish.
Thanks for all the posts, they'll come in handy in the future as I have 3 cavs at mo and 2 don't work. I want to get my 1990 SRi on the road this summer so I may need a bit more help very soon

[Robsey]

Nothing to feel foolish about.

He who never made a mistake, never did anything.

Besides, if you google this forum for "Numpty of the week", you will find virually every post is about me.
*** hangs head in shame ***


It is good to know that it was a simple fix in the end.

[Cavalier342]

Had a feeling it would be something simple like that. Glad you found it.

[Mk3alan]

We've all done it, you think the worst and start looking too deep when often it's something simple!
My Dad used to say when a problem arose - think simple!

Alan

[Joner1983]

It appears I spoke too soon, the EML has returned (not the TC light tho). I've done the paperclip test (cheers Robsey) and I'm getting codes 21, 71 and 31. The light goes out sometimes when I'm driving but eventually reappears. Is it possible 1 or more of these codes would be stored from past problems or is it likely these 3 issues are new?

[Cavalier342]

I think faults are stored in the ECU memory for a certain time, to clear it, you have to disconnect the battery for a certain amount of time, or turn off/on the ignition a certain number of times repeatedly, can't remember how many times. Whether previous faults can throw the light back on again depends really, could be possible, but doesn't usually happen.

[Joner1983]

Cheers for that. I'll probably disconnect the battery overnight and see what happens

[Robsey]

Hmmm - so codes are,

21 =Throttle Position Sensor - High Voltage.

31 = No RPM signal ( possible crank angle sensor fault)

71 = Intake Temperature Sensor - High Voltage.

Disconnect the battery for 15 minutes.

Reconnect the battery and re-do the paper-clip test.

Then go for another spin.

Re-check for fault codes.

Any codes showing now will identify the items needing attention.
Any historic / old codes will have been cleared when the battery was disconnected.

Also check your injector loom ground / earth connections.

From memory,
If you do not disconnect the battery, then the code should not clear until you have had 25 fault free engine starts.