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La sola lupo
85 R11TS, 85 R9TXE, 97 Extra 1,9D, 97 Megane 2.0 RXE, 02 Clio 1,2 16V
1,804 Posts
Discussion Starter · #1 ·
I'm looking at a 97 megane 1 1.6 8valve with a K7M A 7702 at the moment, the car had the clutch replaced, apparently the mechanic did not disconnect the battery when taking out the g/box.

After the clutch was replaced the car no longer starts.
Renault apparently says that the ecu is fried, something about one of the pins giving only 8volt instead of 12v.

From what i can see the car does not have a factory fitted immobiliser, no IR reciever in the roof.
The battery was flat and I didnt have a jump kit with me to do the normal checks, the car has been standing a while.

Question1: Could it have a RF immobiliser?
2:Is there any way to test the ecu without fancy equipment?
3:Can the ecu be fixed DIY?
4:Apart from earth problems can anyone suggest any checks?

Thanks in advance, any help is appreciated.

Premium Member
566 Posts
I would check the engine earths in case these have been disturbed, there is two just above the alternator, it does sound too old to have RF locking, but if you flip the panel out above the mirror the receiver will be there. Also check the fuel cut of switch has not been knocked.

1,343 Posts
A few basic's that needs to be checked. At key on
fuse no 6 5amp feeds inerta switch then travels on
to engine control relay base terminal no 1 . Fuse no 5
30amp at key on feeds base terminal no 3 on same
relay. This relay is activated via a switched earth
at ecu pin no 48. At ecu pin no 32 key off must have
12v's. At ecu pin no 24 key on must have 12v's
ecu earths pin no's 2-3-18 best checked from ecu
multiplug to battery neg Hth Regards Mickeybo

La sola lupo
85 R11TS, 85 R9TXE, 97 Extra 1,9D, 97 Megane 2.0 RXE, 02 Clio 1,2 16V
1,804 Posts
Discussion Starter · #4 · (Edited)
Thanks Rentech and Mikeybo i will check your suggestions.

I assume the ecu pins are numbered?
I dont know these 1.6 engines well, where will I be looking for the fuel cutt off switch?

La sola lupo
85 R11TS, 85 R9TXE, 97 Extra 1,9D, 97 Megane 2.0 RXE, 02 Clio 1,2 16V
1,804 Posts
Discussion Starter · #5 ·
Okay so here is what I have after fitting a fresh battery:
All earths are good
Pin 2,3,18 earths are good
32 has 12.28v at key off and key on
24 has 12.18v at key on
48 has 11.8v at key on
-I didn’t bypass the inertia switch as the pump does pressurize, although it is intermittent from the relay, it goes on-off, on-off, on off with about 1 second intervals.
When I bridge the relay, the pump runs constant.
The relay coil gets 12.2v and the feed for the pump from the relay gets 12,38v

-I found that the immobilizer works with transponder key(chip in key head but no battery), put the key in the ignition and switch on, the red light stops flashing, illuminates for about 3 sec then goes out, dash warning light come on but the mileage display and trip meter doesn’t (which worries me)
-The cabin fan didn’t work, I found the relay next the battery to be faulty, replaced that, now the fan works. I opened up the old relay and found that the diode inside popped.
-The central locking fitted seems to be after market along with an additional RF immobilizer and alarm, which also seems to be working correctly. (The car is a Megane RN 1,6e)

There is no spark to the plugs and the injectors doesn’t seem to fire

On the ecu pins 1,7,10,14,21,22,23,25,26,27,39,,41,47,49,53,54,55 are not connected
The following measurements were taken with the ecu plugged in and the key on:
2. 0,8v
3. 0,8v
4. 0,38v
5. 0.8v
6. 0.8v
8. 0.8v
9. 0.45v
11. 0.38v
12. 11.02v
13. 5.3v
15. 0v
16 4.75v
17 0.4v
18 0v
19 1.5v
20 3.4v
24 12.18v
28 12.18v
29 12.18v
30 0.035v
31 0.75v
32 12.28v
33 3.92v
34 3.92v
35 0.45v
36 0.45v
37 1,83v to 4.16v (it goes up and down all the time)
38 0v
40 0.47v
42 0.32v
43 12.23v
44 0.75v
45 5.8v
46 0.75v
48 11.8v
50 0.45v
51 8.78v
52 0.3

The people she had the car to says:”injector computer to be replaced injector computer shows 8v instead of 12v” I’m guessing this was on a diagnostic machine

The coil connector’s measures
Pin 1 12v
Pin 2 0v
Pin 3 -11,8 (I assume its an earth)

Coil resistances measures
Between pin 1-2. 0.4 ohm and 0.5 ohm
Between pin 1-3. 0.9 ohm and 1 ohm
Between pin 2-3. 0.9 ohm and 0.9 ohm
Between HT and HT 9.88K ohm and 9.81K ohm

Sorry for the long post, but any help will still be much appreciated

La sola lupo
85 R11TS, 85 R9TXE, 97 Extra 1,9D, 97 Megane 2.0 RXE, 02 Clio 1,2 16V
1,804 Posts
Discussion Starter · #7 ·
I return with a red face.

When I checked pin 2 and 3 I tested continuity to earth which was fine.
What it comes down to, I opened the wiring loom and found the wire from pin 2 and 3 joined inside the and a little further down it was broken.

Now the car starts but it starts damn hard when cold, im geussing 8months old petrol will play a part but then it will do the same when hot and the power seemed okay on a short road test after getting it started.

The speedo problem seems to be that the LCD back light is dead
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