Where is the inertia switch located
Where is the inertia switch located
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Discussion

Peppe

Original Poster:

376 posts

251 months

Wednesday 9th April 2008
quotequote all
Hi !

I have been reading some manuals for the Cerbera this morning and found that the inertia switch could turn the mil light on, and probably you won´t get a faultcode on the ECU software if this happens (see my other topic I started yesterday).

Where exactly is the inertia switch located ?
If anyone has some pics that show the location and how the switch looks, it would be very helpful.

Peppe

pjenni12

98 posts

235 months

Wednesday 9th April 2008
quotequote all
the inertia switch is above the fuel tank on the left hand side. You need to pull back the velcro carpet cover and its attatched to the rear bulkhead.

One thing though, I thought the inertia switch if tripped disconected the supply to the fuel pump. If so I can't see how its possible to have the engine running and the mil light on?

Phil

coey 4.2

67 posts

227 months

Wednesday 9th April 2008
quotequote all
pjenni12 said:
the inertia switch is above the fuel tank on the left hand side. You need to pull back the velcro carpet cover and its attatched to the rear bulkhead.

One thing though, I thought the inertia switch if tripped disconected the supply to the fuel pump. If so I can't see how its possible to have the engine running and the mil light on?

Phil
Hi, yes you are spot on, the inertia cuts the fuel (if you have a accident)

julian64

14,325 posts

284 months

Wednesday 9th April 2008
quotequote all
I think you are going to have to try a replacement ECU to see if that solves the problem


mikesr

672 posts

261 months

Wednesday 9th April 2008
quotequote all
The very first thing I would try (if you haven't already done so) is checking for water collecting in the ECU connector.

If water gets in above the passenger knees (heater pipes, harnesses, power cables etc all come through the bulkhead there) the water tends to run down all the dangling wires. It gets inside the insulation on the ECU harness and makes it way into the connector. You can get all sorts of funnies happening when the pins are being connected together via a film of water smile

Whilst you have the ECU out check for corrosion on the terminals and use some contact cleaner and then wd40 to dispel any moisture.

Having said all that, the couple of times I have had water get into the ECU errors were logged.

Another possibility might be a duff NVRAM in the ECU. (Non volatile memory where the adaptive maps and faults are recorded)

Are the adaptives being updated and retained when the car is running. If not then its definitely the NVRAM.

julian64

14,325 posts

284 months

Wednesday 9th April 2008
quotequote all
Anyone know which pin the Mil light goes in on the connector, and I'll look up the circuit on the ECU I currently have in pieces. I think its pin 14, but if someone knows for sure I'll trace it.


Edited by julian64 on Wednesday 9th April 15:21


Edited by julian64 on Wednesday 9th April 15:23

mikesr

672 posts

261 months

Wednesday 9th April 2008
quotequote all
Yes MIL and Buzzer pin 14 wire colour is Black x 2



Peppe

Original Poster:

376 posts

251 months

Wednesday 9th April 2008
quotequote all
mikesr said:
The very first thing I would try (if you haven't already done so) is checking for water collecting in the ECU connector.

If water gets in above the passenger knees (heater pipes, harnesses, power cables etc all come through the bulkhead there) the water tends to run down all the dangling wires. It gets inside the insulation on the ECU harness and makes it way into the connector. You can get all sorts of funnies happening when the pins are being connected together via a film of water smile

Whilst you have the ECU out check for corrosion on the terminals and use some contact cleaner and then wd40 to dispel any moisture.

Having said all that, the couple of times I have had water get into the ECU errors were logged.

Another possibility might be a duff NVRAM in the ECU. (Non volatile memory where the adaptive maps and faults are recorded)

Are the adaptives being updated and retained when the car is running. If not then its definitely the NVRAM.
There are no sign of water in the footwell or in the connectors to the ECU. The car has been stored in a dry heated garage since october, so if there would have been any water it would have disapered. I will clean and dry the contacts to be sure.
I will try to reset the adaptive maps and see if they get updated when I run the car. I won´t be able to do it before the weekend, working late during the week and snow is falling here today (Sweden), the weatherforecast say that the weather will be better during the weekend.

Peppe

Original Poster:

376 posts

251 months

Wednesday 9th April 2008
quotequote all
pjenni12 said:
the inertia switch is above the fuel tank on the left hand side. You need to pull back the velcro carpet cover and its attatched to the rear bulkhead.

One thing though, I thought the inertia switch if tripped disconected the supply to the fuel pump. If so I can't see how its possible to have the engine running and the mil light on?

Phil
The reason why I got an idea of the inertia switch is that i can´t find where the signal from the inertia goes to the ECU or the mil light and buzzer. Could the inertia have two functions, one that switch of the feed to the fuelpump and one that sends a signal to the mil light and buzzer ?
Will try to go trough the diagrams once more and check how it is connected together.

Peppe