C70 Engine Light Despite Many New Parts-- out of ideas

GDPR · Oct 13th, 2020, 12:30

Hi Everyone,

I have a 2001 C70 2.4T which has a fabulous engine but manages to light its orange EML light sometimes. It always resets if I take the battery off.

The light can stay off for ages and then come on when cruising at a constant pretty low speed, around 30-40mph. On the other hand, this is the most reliable car I have had and I trusted it to take me to Switzerland and back during lock down and it didn't light up.
12 hours door-to-door at the maximum speed allowed on whatever road I was on (so 140kph on the GPS when possible, indicated approx. 88mph) and recorded an average MPG on this trip of high-20s.

I have had thecode read multiple times but sadly don't have it to hand as I've changed phone and lost the pic. It was always 3-way caltalyser efficiency

The car has has the PCV system replaced, including the heated pipe,
Injectors overhauled,
Properly serviced and running Castrol Edge oil and only drinking top grade fuel,
Lambda sensors-- both and proper Volvo ones as I've heard

Could the cat really be on its way out? The light used to stay off for months but now seems to come on more frequently but only at these low and constant throttle applications.

The engine is just superb, I can't fault it! Is there anything else on these cars I should be looking at replacing? I dont think I can justify buying a new Cat for it as I presume this is very expensive and the car runs just fine and doesn't seem any thirstier on fuel that the published figures suggest (not that it is good on fuel!).

GDPR · Oct 13th, 2020, 12:39

I should also add, that the car was read with a Vadis machince and had no codes of relavance to the engine at all (just the alarm siren battery) and the WTC light comes on and goes off as it should. In the service history, it has had a "new" (maybe just new to the car) wireless throttle body in the past.

I'm out of ideas now!

Derek UK · Oct 13th, 2020, 14:44

Can this be cured by using an oxygen sensor spacer? I'm sure someone here will have knowledge of this. Expensive from IPD, cheap on eBay.

GDPR · Oct 13th, 2020, 14:47

Quote:

Originally Posted by Derek UK

Can this be cured by using an oxygen sensor spacer? I'm sure someone here will have knowledge of this. Expensive from IPD, cheap on eBay.

That's interesting. So it moved the probe away a little and reduces the strength of the CO reading?

petercz · Oct 13th, 2020, 20:37

Probably wasn't read properly, if the engine light was on, some code must be stored in memory! Find someone with Vida and Dice tool...

PNuT · Oct 14th, 2020, 03:57

Quote:

Originally Posted by petercz

Probably wasn't read properly, if the engine light was on, some code must be stored in memory! Find someone with Vida and Dice tool...

I will have a look later, but I think I went to sort out the SRS light

GDPR · Oct 14th, 2020, 10:10

Quote:

Originally Posted by PNuT

I will have a look later, but I think I went to sort out the SRS light

Hello. Yes, you did sort out my SRS light which I'd latched on when changing the seats. Thanks for that. All good on that front!

When I say I've had the code read in regards to this intermittent EML, I mean by friends who are mechanics who hae expensive (but not VADIS) machines at thier work. I had them read it when the light was on, before I disconnect the battery to clear it.

If the VADIS can read historical faults then that would be a good next step too. When you came, I think it had been behavng for some time.

GDPR · Oct 14th, 2020, 14:20

I've just re-read the thread ad realise that I've written about the codes in a confusing way.

To clarify:
When the EML is on, the code is read as 3-way catalyser efficiency
When the EML is reset, there are no active codes.
I believe it is triggered when a higher-than-the-limits allow CO content is detected post-cat. Most of the time it doesn't trigger the EML as it is only a continuous light application of the throttle that makes it come on (and stay latched on until reset).

I forgot to add that itr has also had a new coolant temperature sensor, just incase that was causing thengine ECU to read the wrong temp and set the mixture wrong

sdg1970 · Oct 14th, 2020, 15:01

My old (ME7) V70 2.4T used to throw a relentless P0422 code. This happened after I fitted all new, gen Bosch 02 sensors and MAF to get rid of a 172 & 171 codes (amongst others, which I forget now). It never failed an mot on emissions subsequently, so I just used to check and cancel the code now and then and carry on.

GDPR · Oct 14th, 2020, 15:32

Yeah, its very picky this post-cat limit isn't it!

Forgot to add also that the MAF was replaced by previous owner, so is only a few years old, but I did clean it with MAF cleaner.

Oct 13th, 2020, 12:30	#1
GDPR USER DELETED FOLLOWING GDPR REQUEST Last Online: Aug 5th, 2021 09:40 Join Date: May 2009 Location:	C70 Engine Light Despite Many New Parts-- out of ideas Hi Everyone, I have a 2001 C70 2.4T which has a fabulous engine but manages to light its orange EML light sometimes. It always resets if I take the battery off. The light can stay off for ages and then come on when cruising at a constant pretty low speed, around 30-40mph. On the other hand, this is the most reliable car I have had and I trusted it to take me to Switzerland and back during lock down and it didn't light up. 12 hours door-to-door at the maximum speed allowed on whatever road I was on (so 140kph on the GPS when possible, indicated approx. 88mph) and recorded an average MPG on this trip of high-20s. I have had thecode read multiple times but sadly don't have it to hand as I've changed phone and lost the pic. It was always 3-way caltalyser efficiency The car has has the PCV system replaced, including the heated pipe, Injectors overhauled, Properly serviced and running Castrol Edge oil and only drinking top grade fuel, Lambda sensors-- both and proper Volvo ones as I've heard Could the cat really be on its way out? The light used to stay off for months but now seems to come on more frequently but only at these low and constant throttle applications. The engine is just superb, I can't fault it! Is there anything else on these cars I should be looking at replacing? I dont think I can justify buying a new Cat for it as I presume this is very expensive and the car runs just fine and doesn't seem any thirstier on fuel that the published figures suggest (not that it is good on fuel!).

Oct 13th, 2020, 20:37	#5
petercz Member Last Online: Apr 16th, 2024 16:58 Join Date: Aug 2011 Location: CZ	Probably wasn't read properly, if the engine light was on, some code must be stored in memory! Find someone with Vida and Dice tool... __________________ '96 850 R, B5234T5, AW42-50LE \| '89 764 GLE, D24TIC, ZF 4HP22 '97 944 Turbo, B230FK, M90 (145kW/330NM - Vialle LPi, BTI chips, 16T@0.8bar, 3"DP+2,5"cat-back, wasted-spark, DO88 IC, Bilstein B6, lowered, dual-sways...)

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Oct 13th, 2020, 12:39	#2
GDPR USER DELETED FOLLOWING GDPR REQUEST Last Online: Aug 5th, 2021 09:40 Join Date: May 2009 Location:	I should also add, that the car was read with a Vadis machince and had no codes of relavance to the engine at all (just the alarm siren battery) and the WTC light comes on and goes off as it should. In the service history, it has had a "new" (maybe just new to the car) wireless throttle body in the past. I'm out of ideas now!

Oct 13th, 2020, 14:44	#3
Derek UK VOC Member Last Online: Yesterday 13:53 Join Date: Jul 2006 Location: Chatham	Can this be cured by using an oxygen sensor spacer? I'm sure someone here will have knowledge of this. Expensive from IPD, cheap on eBay.

Oct 14th, 2020, 14:20	#8
GDPR USER DELETED FOLLOWING GDPR REQUEST Last Online: Aug 5th, 2021 09:40 Join Date: May 2009 Location:	I've just re-read the thread ad realise that I've written about the codes in a confusing way. To clarify: When the EML is on, the code is read as 3-way catalyser efficiency When the EML is reset, there are no active codes. I believe it is triggered when a higher-than-the-limits allow CO content is detected post-cat. Most of the time it doesn't trigger the EML as it is only a continuous light application of the throttle that makes it come on (and stay latched on until reset). I forgot to add that itr has also had a new coolant temperature sensor, just incase that was causing thengine ECU to read the wrong temp and set the mixture wrong

Oct 14th, 2020, 15:01	#9
sdg1970 Master Member Last Online: Jan 19th, 2024 17:18 Join Date: Jun 2012 Location: Hell	My old (ME7) V70 2.4T used to throw a relentless P0422 code. This happened after I fitted all new, gen Bosch 02 sensors and MAF to get rid of a 172 & 171 codes (amongst others, which I forget now). It never failed an mot on emissions subsequently, so I just used to check and cancel the code now and then and carry on.

Oct 14th, 2020, 15:32	#10
GDPR USER DELETED FOLLOWING GDPR REQUEST Last Online: Aug 5th, 2021 09:40 Join Date: May 2009 Location:	Yeah, its very picky this post-cat limit isn't it! Forgot to add also that the MAF was replaced by previous owner, so is only a few years old, but I did clean it with MAF cleaner.

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