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Discussion Starter #1
Hi all,

I found some info on handbrake problems in the forum and some people seem to have an intermittent warning "Service Parking Brake" on the dash but tend to ignore it.

Mine started a week ago: Symptoms:

  • Intermittent warning that goes on and off, including whilst driving
  • Sometimes handbrake will not apply
  • Sometimes if applied it won't release using the dashboard switch but will disengage normally if I just drive off gently.
  • Sometimes when it will engage the orange symbol on the dash that flashes and then goes solid when the brakes are applied doesn't go solid but the brakes are on.
I tried one suggestion on here about using maximum foot brake force while switching the handbrake on and off but that hasn't helped.

Has anyone else had similar or could tell me where to start fault finding?

OBDII shows only the usual charge door error.

Many thanks in advance

Nick
 

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I was going to suggest checking your 12v battery, but it can't be anything to do with it as the car's DC/DC converter would be charging it when the car is on anyway...

The rear calipers are Astra parts, and so it seems is the handbrake motor unit (rather than a Volt specific one). In which case it most likely will need a new motor unit - part no. A2C30124400 AFAIK - which should be do-able by any garage (or DIY if you can get underneath). Potentially the cable just needs adjusting but I doubt that could cause a warning whilst driving. Don't see how applying braking pressure could make much difference, the cable pulls a mechanical lever on the caliper - it doesn't apply hydraulic pressure.

Good luck and let us know how you get on
 

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Discussion Starter #3
Thanks Modo,

I did some OBD checking but with my kit only got the standard charge-door sticky error

I did find the following in the manual:

Hand brake Cable Adjuster Disabling


The hand brake cable tension is controlled by the electronic hand brake (EHB) module. Tension can be fully released from the hand brake cables to allow for service of the
hand brake system. Perform one of the following three methods to fully release cable tension.

Electronic Hand brake Cable Tension Release

Without Scan Tool - Optional Method

1. Block the drive wheels.

2. Turn the ignition switch to the ON/RUN position with the engine OFF.

3. Place the automatic transmission in PARK or manual gearbox in NEUTRAL, as equipped.

4. Apply and hold the brake pedal. The brake pedal must remain applied throughout the hand brake cable tension release process.

5. Press and hold down the electronic hand brake (EHB) switch approximately 5 seconds.

6. Observe the HAND BRAKE lamp on the instrument cluster.

7. When the HAND BRAKE lamp flashes, release then immediately press and release the EHB switch.

The hand brake cable tension is fully released.

8. Release the brake pedal.


Hand brake Cable Adjuster Enabling

The hand brake cable tension is controlled by the electronic hand brake (EHB) module. Cable tension needs to be set and the EHB module needs to be calibrated following
the cable tension disabling procedure. Perform one of the following two methods to fully restore cable tension.

Electronic Hand brake Cable Tensioning

Without Scan Tool - Optional Method

1. Block the drive wheels.

2. Turn the ignition switch to the ON/RUN position with the engine OFF.

3. Apply the brake pedal.

4. Place the automatic transmission in PARK or manual gearbox in NEUTRAL, as equipped.

5. Momentarily lift then release the EHB switch to apply the EHB.

6. Momentarily press down then release the EHB switch to release the EHB.

7. Repeat step 5 and 6 to cycle the EHB on then off an additional 4 times.

8. The EHB module will be calibrated and proper tension will be applied to the hand brake cables.

Which I guess is why some folks have had luck with this. At a moment when it was working I did the above but to no avail.

I jacked up the car, pulled the wheel off and the wheel arch liner to have a look at the control unit and motor to find that it's really exposed to the elements behind the rear wheel and the case for the controller has rusty nuts etc. I re-seated and electrolubed the multiconnector but that didn't do anything - when the system works it seems to work fine. I can just be sitting still in the car and the error will show and then disappear again. I can get the error to go by unplugging the control unit and plugging in again - which is leading me to think that this is where the problem lies.

I have ordered an Op-com OBDII adapter to see if the car will tell me why it thinks that there is a fault. Failing that I'll ask the dealer - it's due a service. If they say it's a new unit needed I'll try and source a recon - looks very easy to refit.

I'll keep you posted.

Thanks again

Nick
 

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Most standard OBDII readers won't display brake system components such as ABS or EHB messages. you either need dealer scan tools or there are dedicated tools which claim to access theses sytems.
 

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If you are I'm Dorset, I have GM gds2 which I'm figuring out...
 

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Used units on eBay are under £100 so if you can get to it simply by taking a wheel off (I noticed it when I replaced my rear brake pads, but don't remember exactly how easily acessible it was) might be cheaper to swap the unit rather than pay for dealer diagnostics.
 

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Discussion Starter #7
Thanks Modo - Yes may be a better option, the unit looks really easy to change however not sure if an Astra one will need reprogramming (££££)

Thanks for the offer HughF - I'm in the Cotswolds though

A friendly mechanic I know stuck it on a ££££££ scanner - it detected a C0293 Handbrake switch fault.
There's a set procedure to follow to test it in the manual.
Looking at the schematic this means that there is a connection problem between the control unit in the wheel arch and the switch or the switch itself.- I'll get a chance later in the week to get the ammeter out!

While I had my Dongle and TORQUE running I thought that I would clear the charge-port error that was stored.
When I did so the ICE started up, and I got a REDUCED PROPULSION message and MIL. Unable to clear the DTCs - Drat.

However, left car plugged in - it says it wasn't charging and the green/orange charge dome was black but when I went back the car half an hour later all was back to normal albeit with the MIL light still on.

Not sure what's going on. Will have to wait 'till my new scanner arrives on Thursday to try and clear the new DTCs


Screenshot_20190223-191235.png
 

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Discussion Starter #9
Possibly Russ, I'll have a measure
I drove it today for 1/2 mile stopped for 10 minutes - got in to drive back and the MIL had gone out

Plugged in the voltec charger when I got home - it wouldn't charge
now getting error warning on the charger when not even plugged into the car :-( will post again

even the kit car ECU fried itself today - Not a good day!
 

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D'oh, sorry to hear that! The main 12V battery is the first thing to consider though when weird things happen on the Ampera/Volt and you get lots of error codes that don't make sense.
 

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Plugged in the voltec charger when I got home - it wouldn't charge, now getting error warning on the charger when not even plugged into the car :-( will post again
I wouldn't trust the supplied granny charger to test the car as mine has failed twice. The second time I stripped the thing down to find it worked happily with its guts exposed!
It still works glued back together but the moral of the story is that ideally you need to test charging on a proper EVSE and check the voltage of the battery after leaving overnight directly on the terminals and before powering up. It should be over 12.5v.

I think it dips momentarily as the DC contactors pull in and causes so many stupid error codes and faults.

A supercap on the power line of the ECU's would have saved so many problems on these cars and can only assume that ICE electronics have them by the bucketload as they still seem to perform even when the battery is cranked down below 9v!
 

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Discussion Starter #12
Have monitored the voltage with MyGreenVolt - started with 15v! then reduced to 14.3 by the time I got to work.
Had the error all the way.
Car was left in the sun all day and no error on return in the evening even down to 2 degrees. - no error this morning either. I'm wondering if damp has got into cables/plugs. On the mulitplug in the back of the control unit (which is behind the wheel arch liner but still exposed to the elements from a gap in the bodywork towards the middle of the car), I can see all the individual wires going into the back of the plug. I would have thought that there would have been some sort of protective shield around them.
Anyone else had their's out and remember what it was like - if the error stays gone then I may stick some silicone sealer over the wires to try and keep moisture out
 

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You still need to check the battery volts before powering up at the battery. Might be dipping low and giving the fault but also if you have exposed wires sealing them when dry isn't a bad idea.
 

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You still need to check the battery volts before powering up at the battery. Might be dipping low and giving the fault but also if you have exposed wires sealing them when dry isn't a bad idea.
Can second this as I recently had a long list of error codes cured by a new 12v battery. You need to measure it when the car has been switched off - leave your boot open for 15min after switching off as even opening the boot can turn on the DC-DC converter. Try turning the headlights on (with the car not switched on) if it dips below 12v I'd bet your battery is the culprit.
 

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Discussion Starter #15
Thanks both...

Damp and wet again today and the error is back.

I will definitely check the voltage in the boot tomorrow - thank you

The error has appeared when driving - so may be not 12v but will definitely check

OpCom adapter arrived today and confirmed C0293 06 or C0293 08. I cleared the codes and got C0293 06 back immediately. So if not 12V I know where to start hunting.

Will keep you updates :)
 

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Discussion Starter #17
Thanks H8ten, I already had the full manual- It also has schematics.
Followed Russ's advice above - Battery voltage 12.82v

Took dash apart (surprisingly easy) took the switch out and tested as per manual. All the open circuits fully open and all the closed fully closed and switch functions correct. I did notice that someone had been there before me! there was a small stretch of one of the wires supplying the multiplug on the back of the switch had a bit of insulation stripped back and covered with insulating tape. The sort of strip back you would make to attach a probe. Some of the trim wasn't put back right either.

Next I tested all the multiplug connections for short to earth and 12v etc as per manual. One of the pins that should have been infinite resistance to ground was showing 7k ohms.

I'm hoping this could be water ingress at the controller end of the cable. Mechanic at work thinks it could be likely.
Hopefully next time it's warm at home I can seal it all if the error goes away again.


Also - for others - after disconnecting the battery a few times The car decided to give no HV Battery status and no propulsion. OPCOM had an engine DTC that said that the Electric traction control module had requested a MIL and it wasn't clearable. NO ICE or anything. :-(
The Traction module showed no DTC. Thinking I would need recovery and someone else to do the school run I tried a 12V battery disconnect and reconnect. All was well ???

Will further update

Have a nice weekend all - I'm at work so no more playing for a few days.

On the plus side I did get the Kit Car ECU reprogrammed and working again!

Nick
 

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Discussion Starter #18
The weather has been better here so I took out the control module and switch again and retested all the wiring. - All seem OK except the pin 5 on the switch plug doesn't read correct voltages from the control box -
I can see that that this wire has been stripped on the back of the switch plug and the back of the control box connector to have diagnostic leads clipped on so it's had this problem before I think. (this wire is Battery positive B+ supplied by fuse F10DL (also does interior lights and brake lights). When I should have been seeing 12v I was seeing 6v and if I kept watching the voltage would slowly drop.

I then checked for other items fault codes in the car and got U1280-00 (lost comms between brake control module and parking brake control module) . Again one of the reasons could be the B+ voltage.

So I started looking elsewhere and saw that both of the left brake light clusters had water ingress - steamed up on the inside. I can also see from body damage that it looks like the outer one has been taken out before.

You can isolate the rear lights by detaching the supply harness at the bodywork inside the access panel on each rear corner in the boot. I had water ingress in the door mirror housing too - this can be isolated by the connector in the door jam. Sadly, neither fixed the problem for me :-(

Tried a new Parking Brake control module - that didn't work

Tried testing the switch again and all checks out OK - just to be sure, replaced the switch with wire links - still has the fault

Hmmm - running out of options
 

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These are always difficult to fix, the wiring is made up of sections with connectors at stategic points, it tells you in the wiring diagram where they are. In this case you have to find the poor connection that's dropping your voltage to 6 volts on B+.
That means disconecting the wiring so you can check the resistance of the cables, lots of taking apart to get at things but relatively easy to do with the right equipment ( miliohm meter ) then splice in a bypass or replace the connector.
 

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Does sound like moisture if its giving 6v. I wonder if removing fuses would be any use in diagnosing - suspect not, as it sounds like shared circuit is all running off one fuse. Not a fun project, but hopefully you'll find the problem area and should be an easy fix from there.
 
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