240 lamda light

240 · 2017-03-27T08:04:22+00:00

I may be wrong, but I believe that lambda sond light is actually the 'check engine light'. 92 is LH 2.4. Have you done the dance with the diagnostic conn...

240

There is a very slow leak from the thermostat housing - I don't think I put the seal in properly.
How does it affect things though?

Excuse my ignorance, what's the CTS?

deleted_user_2040

Coolant temperature sensor

Major Ledfoot

Coolant Temperature Sensor - oops, sorry, I lapsed into GM-ECM-talk mode... I meant ECT. It's the second one in the head, near #3 inlet, for the LH 2.4 system.

Green book recommends checking for a bad connection in grounding or of wiring, or contact resistance in connections, or a poor signal ground connection.

Code 1-2-3 will set if a temp of -40C (25K ohms+) or lower, or higher than 120C (about 110 ohms) is seen by the ECU.

240

120°C... I guess it could have come close to that. What's normal operating temp, about 90?
I'll have another fiddle round and see if I can get the code to clear.

Major Ledfoot

Feel free to correct me if I'm wrong, but normal temp is around 90C, yeah. Generally around the temp of your thermostat.

OTOH, 120C is very hot.

A pressurized system will allow the water (coolant) boil at a higher temp than 100C. Trouble is, if the temp faker is cactus, you're not seeing the coolant temp going into the red. But the temp sender for the temp gauge is a different beastie to the ECT.

BTW, resistances mentioned above are from pin 1 of the ECT sensor to ground.

caerleon

ignore it. If u have problems with the mechanicals of your car you'll know.

caerleon

earlier model 244's don't have these types of alarms, and they seem to go on forever

240

I'm not going to ignore it. Maybe if it was a beaten-up workhorse of a car the I would, but it's my daily driver and the car is in good condition.
Later 240s have EFI, so the electronics are just as important as the mechanicals.

And the later ones go on forever too, they just have more advanced computers.

@Major Ledfoot now that I think about it I don't think it could have reached 120°C. It's only ever boiled over once, and that was before I replaced this sensor anyway.
Sorting through some stuff today, I found the old one that I pulled out last time - it has some sort of gunk (calcification maybe?) on it. I know that the one I replaced it with didn't have that, so my plan is to clean the gunk off the old one, put it back in the car, and see if the new one now has the same stuff on it. If so, I'll go from there and work out why.

Major Ledfoot

Ignoring it means leaving the car running in limp home mode, which also means reduced performance.

Gunk on the sensor might affect the readings so they're low, but 1-2-3 indicates a loss of signal. So I'd be checking the wiring, looking for bad grounds or corrosion on connectors. Trouble is, the ECT connector is in a real beech of a position to get to and test.

240

1-2-3 is "ECT signal faulty or missing" - so if the wiring is fine, it could be 'faulty' due to the gunk, rather than missing.
But yeah I might as well go over the wiring while I'm at it.

Vee_Que

Not likely, they are sealed, but the sensor itself needs to be tested or fitted with a known good one. The fact it stopped when you disturbed the wiring tells me most of what I need to know.

240

Vee_Que;127465 wroteThe fact it stopped when you disturbed the wiring tells me most of what I need to know.

Not sure where you got that from? I haven't disturbed the wiring, the fault just came on randomly one day.

jamesinc

@240 if you want to check wiring, the ECT should have continuity to ground on the brass body of the sensor, and then continuity to pin 13 on the ECU and pin 2 on the EZK module. With engine at OT, the ECU pin should read ~350mV, and the EZK pin ~1.5V. With a cold engine, both those values should be higher. The wires are blue with a red stripe (I think - probably just pull the connector boot back and check).

240

Thanks for the advice James.

@bgpzfm142 and others - I pulled off the sensor's connector today and it looked a bit dirty and corroded, so I tried to give it a bit of a clean in the hope that that would fix it.

However I can't clear the codes!

The instructions I have say to insert the probe in the appropriate socket and read the codes as normal, then to press the button for more than 5 seconds. It says that after 3 seconds the LED should light, then press it for another 5 seconds.
I am following the instructions exactly, but when I press the button for more than 5 seconds, the LED is lit the whole time - rather than coming on after 3 seconds...

Maybe I'm just not following the instructions properly but can anyone work out what I'm doing wrong?

Major Ledfoot

You can do a cheat to clear the codes - just disconnect the car battery for about 5 minutes. Just be sure you have your radio PIN code handy before you do! :)

240

Of course... Thanks. Code cleared now, hopefully it won't come back.

timbo

This is how i clear the codes
Read the codes twice (as in let it repeat all of them)
Hold the button for 20 seconds
Let go of button
Led will light up solid
Hold it down for another 20 seconds

jamesinc

@timbo 5 seconds is enough to clear codes! Just count them slowly.

jared244

check which ecu your car has. I had a intermittent recurring fault code related to the MAF in my 91 240 and changed everything trying to solve it. Turned out to be the ecu.

There was a run of ecus with a pink label which are particularly bad for becoming faulty and causing false sensor problems. Sometimes as bad as the car not running at all.

240

Actually I have heard of that ECU fault so I will check that. Particularly as the light has now come on again.

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