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MIL Alarm Camry 2.2 1995

Tiny
VINCENT.HKCHUA
  • MEMBER
  • 1996 TOYOTA CAMRY
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 205,000 MILES
I have a Toyota Camry 2.2 - 4 cylns 1995. There is a MIL alarm and when I short TE1 and E1, I get a diagnostic code of 12 based on the flashes. Which mean that engine revolution signal missing. Do you have a drawing indicating where is the location of this sensor? Can this sensor be repaired? If not, is it still available and how much would it cost roughly?
Thanks

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Sunday, May 22nd, 2011 AT 4:44 PM

10 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
This usually means a problm with the distributor. Sorry I am not sure of the costing and it is best to get local quotes to be accurate.

CODE 12 - G & NE SIGNAL CIRCUIT (NO. 1) (EXCEPT CALIF.)

Circuit Description
The distributor or Integrated Ignition Assembly (IIA) contains 2 pick-up coils, G and NE signal coils. The G signal pick-up coil sends the ECM standard crankshaft angle. The NE signal pick-up coil sends the ECM crankshaft angle and engine speed. Code is set when there is no NE signal to ECM within 2 seconds after cranking and/or no G signal to ECM for 3 seconds or more with engine speed of 600-4000 RPM. Possible causes are:
†G or NE open or short circuit.
†Distributor pick-up coil(s).
†STA open or short circuit.
†ECM.

Diagnosis & Repair

1. Ensure ignition is off. Disconnect distributor 4-pin connector. Using ohmmeter, measure resistance between specified terminals. See Fig. 3. See G & NE PICK-UP COIL RESISTANCE table. If any resistance measurement is not within specification, replace distributor. If all measurements are within specification, go to next step.

2. Inspect circuits between distributor and ECM for open or shorts. Repair as needed. If all circuits are okay, inspect air gap between each pick-up and signal rotor. If either air gap is NOT within specification, replace distributor. If both air gaps are within specification, replace ECM and retest.
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
VINCENT.HKCHUA
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Dear KHLow,
I have measured the two pick-up coils and they are both within spec.
G+ & G- = 240 ohms (socket side to ECM = 6.5K ohms)
NE+ & NE - = 490 ohms (socket side to ECM = 20K ohms)
None of the pins are shorted to body on both ends. There is only a slight oil leak from the shaft, perhaps the "O" Ring need to be replaced.
Despite the MIL ON, the car is performing perfectly without any problem.
However, when I disconnect the G and NE socket, the engine cannot be started. Meaning the ECM is okay and is getting healthy signal to run the engine when connected. Just my gut feeling, if I am not wrong.

Question 1- Therefore, can this boils down that one of the pick-up is faulty that is creating the MIL alarm but not affecting the car performance. If so, which pick-up coil? The one with single cam or the one with 4 cams? I believe the one with a single cam is the G pick-up coil. Please advise.
Question 2- Does the RPM reading on the dash board come from one of these pick-up coil? (RPM on dash board is working well anyway)
Question 3 - Is there any other fault that can give a Code 12 diagnostic?
Question 4 - What is SPA? Not sure what you mean by "STA open or short circuit".
The MIL is now quite permanently ON when engine is running unlike week before where it came only once or twice in a day.
Your expert advise will help me to narrow down what to change. Pick-up coil, whole distributor or ECM.
Thank you so much.

Regards,
Vincent
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
KHLOW2008
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The socket to ECM ohm readings are rather high indicating a possible poor connection somewhere. This high reading could be the cause of the problem rather than any fault. Recheck all wire connectors between distributor and ECM.

Over here we do not repair /replace pick-up cols because parts are not readily available and if it is a fault with the internal components of the distributor, it is replaced as a unit.
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
VINCENT.HKCHUA
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Dear KHLow,
I am surprise by your quick reply, that's pretty fantastic.

Question 1 - Would you be kind enough to tell me where the ECM is located or if you have a drawing guide on which cable colour to measure at the ECM side?

Question 2 - What would be the normal G and NE resistance reading to ECM?

BTW, do you have any contact in Malaysia where I can send my car to resolve this problem. Or any workshop nearer to Port ****son apart of sending it to the Toyota service centre which is going to cost me a bomb. Are you not from Malaysia?

Regards,
Vincent Chua
(vincent. Hkchua@gmail. Com)
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
KHLOW2008
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Sorry for the delay this time. Had some problem with my internet connections last nite so could not reply then.

ECU is located behind the glove compartment. Diagram is for a LH drive vehicle so for RHD it should be opposite side of vehicle.

Wirings should not have minimal ohms difference bwtween ends, the lower the better. Usually a good wiring circuit would have zero resistance.

Sorry I do not have any contacts in PD, I am based in JB and for the distributor, you should be able to get a used one from the junk yards in Seremban for RM 200 or lower.
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
VINCENT.HKCHUA
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Dear KHLow,
I am also experiencing Internet Explorer slow respond so I have to use Google Crome which I am not too familiar.
Thank you so much for the ECM location drawing, just hope it's the opposite for RH drive. Quite a massive job to open up the dash board.
Hope you get me right, input to ECM from G pick-up coil - the impedance across the pin is 6.5K. And for NE input, across the pin is 20K. As an electronic engineer, it may be quite normal to have high impedance across the pin for certain electronics. If this is really abnormal, as you are the expert, then it would be worth trying to loop check the wire from the socket to the ECM inputs. Which mean I have to strip open the cable sleeves from bonnet to the dash board to trace them since I don't have the drawing or wire colour code.I hope the same colour coding on the socket end can be found on the ECM side as well.
Question 1 - Is the ECM available locally? If yes, how much would it cost roughly for a new one or a used one.
Question 2 - When replacing ECM, does it need any kind of re-programing via a PC?

Regards,
Vincent
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
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You need not open up the dash. Removing the glove compartment would do.

Measuring across pins is not an accurate way of testing. You need to test the resistance between the terminal of ECM to the G or NE terminals.

No, ECM is not easily available as Malaysian and Japan Domestic Models uses different ECM. Good news is the part selsom fails. Since you are familiar with electronics, remove the ECM and check internally for signs of bad capacitors or contaminations. If any found, repair them and you should have the ECM running good again.

No, ECM is a plug-and-use component and the only possibility of getting a replacement is from Singapore junk yards.
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
VINCENT.HKCHUA
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Dear KHLow,
Just to share with you- I think I have resolved my Camry 2.2 MIL alarm based on your guidance.

1) I replaced the distributor with an old one which I kept for a few years.(Working unit but has slight oil leak)Having done so, the MIL is tsill there.

2) I disconnect the battrey and removed the ECM. I found some burnt mark (see attached photos- zoom in to see better)on few of the PCB track. I clean it up and reinstall the ECM. Does not solve the MIL problem either.

3) I remove the ECM again, this time I measured the affected burnt tracks and found one having about 300K ohms (R204 to D203). I relinked it with a small wire and reinstalled the ECM. I kicked start the engine, it rev to 1000rpm, then it slowly crept up to 1400rpm. 20 seconds later it came down to 800rpm and suddenly the the engine stalled. Few minutes later I re-started the engine again, this time it maintain at 800rpm and the MIL did not come on. I have been driving for the past one week without any problem.

Question 1- Did I create another problem when the engine idling went cranky? Or is it that the ECM is initialising itself?

Question 2- Since replacing the distributor, I roughly put it to the same position. Is this OK or do I need to do an engine tune? I only did some minor adjustment to the ditributor to achieve 800rpm. Please advise.

Regards,
Vincent
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
VINCENT.HKCHUA
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Dear KHLow,
Just to share with you- I think I have resolved my Camry 2.2 MIL alarm based on your guidance.

1) I replaced the distributor with an old one which I kept for a few years.(Working unit but has slight oil leak)Having done so, the MIL is tsill there.

2) I disconnect the battrey and removed the ECM. I found some burnt mark (see attached photos- zoom in to see better)on few of the PCB track. I clean it up and reinstall the ECM. Does not solve the MIL problem either.

3) I remove the ECM again, this time I measured the affected burnt tracks and found one having about 300K ohms. I relinked it with a small wire and reinstalled the ECM. I kicked start the engine, it rev to 1000rpm, then it slowly crept up to 1400rpm. 20 seconds later it came down to 800rpm and suddenly the the engine stalled. Few minutes later I re-started the engine again, this time it maintain at 800rpm and the MIL did not come on. I have been driving for the past one week without any problem.

Question 1- Did I create another problem when the engine idling went cranky? Or is it that the ECM is initailising itself?

Question 2- Since replacing the distributor, I roughly put it to the same position. Is this OK or do I need to do an engine tune? I only did some minor adjustment to the ditributor to achieve 800rpm. Please advise.

Regards,
Vincent
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Thursday, December 27th, 2018 AT 1:11 PM
Tiny
KHLOW2008
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When the ECM is disconected, its memory is lost and it does need to relearn and during the process, erratic idling coupled with stalling might occur so if the engine is running well now, there is nothing you need to worry about.

It is best to get a timing light to check the ignition timing and adjust if necessary to get the optimum performance from the engine. The ignition could be too high or low presently though you have adjusted it to as close as possible with initial position.
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Thursday, December 27th, 2018 AT 1:11 PM

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