How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Fixitman Your Own Question
Fixitman, Master Technician
Category: Toyota
Satisfied Customers: 17349
Experience:  ASE Master Certified, AA Degree Auto/Diesel Tech
Type Your Toyota Question Here...
Fixitman is online now
A new question is answered every 9 seconds

The engine trembles so now and then. I'm getting an error

Customer Question

The engine trembles so now and then. I'm getting an error code p1605 on the scan. I've already changed the ecm but still the engine trembles on and off. What could be the problem?
Submitted: 1 year ago.
Category: Toyota
Customer: replied 1 year ago.
I've already changed the ecm, 3 coils and 4 spark plugs.
Customer: replied 1 year ago.
When the engine trembles the engine light turns on and when the engine stops trembling the engine light turns off again.
Expert:  Fixitman replied 1 year ago.

Hello, my name is Bobby. Thank you for the question. Can you tell me if this occurs more when hot or cold and if it happens every time you drive it?

Customer: replied 1 year ago.
It happens more when the engine is hot. It doesn't happen every time I drive. Today for instance it didn't happen. When the engine trembles the car has trouble accelerating. It feels like it's going to choke but it doesn't.Let me give you some history.
It was a second hand car when I bought it in May 2011. All was well until January 2013 when I drove it to some place. I turned the engine off and stayed there for ten minutes are so. When I turned the engine back on it trembled immediately and the engine light was on. I turned the engine off and after a while I turned it on again. By then the engine wasn't trembling anymore. A friend said that it is a warning light so If it would turn back on while driving I could drive on home.
I brought the car to the official mechanic of Toyota here in Surinam but they couldn't find anything. The engine didn't tremble while I was there either. After that the problem became worse. The trembling occurred for longer periods and came more often. In 2013 I've been to the mechanic several times. At first the scan didn't give any information because the engine light was off while I was there. Finally by November 2013 the engine trembled and the light was on while I was at the mechanic so they immediately did the scan and according to them the problem was the ecm. It needed to be replaced. They ordered 1 for me and the delivery would be 4 months later. In the meantime I still drove the car and the engine problem became worse. By the end of December 2013 I was parked at a store on a parking lot. When I started the engine, it trembled and choked immediately. If I would start again it would choke again. I couldn't drive away. After a couple of hours the car could start again and without trembling I could reach my home. After that I didn't drive the car anymore.
March 2014 when the ecm was in I brought the car to the mechanic with a tow truck. They replaced the ecm and said they needed to replace coil no. 1 as well. I said ok. When I got the car it drove fine for about 3 months. Then I experienced the same trembling of the engine. When I confronted the mechanic of that, they said I needed to replace coil no. 2 (it's like changing light bulbs. By the time you have to replace 1, you actually need to replace all of them). So they replaced coil no 2. Again after that the car drove fine for 3/4 months but then the same problem occurs. So they replaced coil no 3. And again after 3 months or so the same trembling of the engine. In December I brought the car to a different mechanic than before. They looked at it and saw some ash residue in the opening of coil no. 1 (the one that was first replaced). They found nothing wrong about coil no. 4. They said that coil no 1 wasn't good, so replaced that one again. After that the car drove fine for 8 months but now I have the engine problem for the umpteenth time. Last Tuesday the car was scanned again and the error message p1605 knock control malfunction (cpu) came up.Please give me THE solution.Regards
Expert:  Fixitman replied 1 year ago.

Thanks for the response. It does not sound like a computer issue. They need to so a hot and cold compression test on the engine. This engine has a history of failures with the valve seats. This can cause a compression issue at intermittent times. Most of the time the compression test will show this.

Customer: replied 1 year ago.
Ok thank you. I have an apointment with the mechanic on Monday. I'll let them do the test and let you know how it went.
Expert:  Fixitman replied 1 year ago.

Thank you. Let me know what happens and we can continue if needed.

Customer: replied 1 year ago.
They did the hot compression test today but they didn't notice any irregularities. They said that the readings from the 4 cylinders were ok and the same. They still have to do the cold compression test. The vehicle is too hot now. Do you know of some other test they can do, so that once the car is at the mechanic they can do them subsequently?
Some extra information: They connected the old ecm that I replaced 17 months ago to the car and the car did not respond to it at all. It wouldn't start, nothing. They put the ecm that I now have back in the car and everything was ok again. No error (P1605) message on the scan anymore. So I believe the error message comes and go also.
Expert:  Fixitman replied 1 year ago.

If they do not find any issues at all when they finish the compression test then they need to try running some intake cleaner like Seafoam through the engine to see if it has any carbon build up. If that does not help then you may have an issue within the wiring harness.

Customer: replied 1 year ago.
Ok thank you. I'll do as you say and let you know asap.
Customer: replied 1 year ago.
They did the cold compression test but again no irregularities.
They're looking for the Seafoam or something like that to check the carbon build up on Monday.
They said that if the problem is in the wiring harness it will be very difficult to find because of the magnitude of wires and the scan does not point out which wire.
Expert:  Fixitman replied 1 year ago.

They are right that it is very difficult to find a wiring issue. After they try the Seafoam let me know what happens. Thanks for the update.

Customer: replied 1 year ago.
I couldn't find the sea foam or anything like it in Surinam, so I ordered it online. I should have it by the end of this week. In the meanwhile the mechanic here has checked the charge on the wiring of the ecm, coils and sensors. But didn't notice anything out of order.Yesterday I noticed something while I was driving and the problem occured again. I already mentioned that the car has trouble accelerating when the motor trembles and the engine light is on. I also noticed that if I step on the gas very hard the car has trouble shifting gears. The revolution counter will go above 3 very fast and stay there for a relatively long time before eventually shifting gear at almost 60km/h. I also noticed that if the car is stuck in one gear and I move my foot from the gas pedal and then step on the pedal again, the car will shift to the next gear.
When I accelarate slowly I don't have this. The car still has trouble accelerating but it will shift gear in a timely manner. The revolution counter wil not go above 3.Does this info give new insights?
Expert:  Fixitman replied 1 year ago.

Are you still getting the same computer codes?

Customer: replied 1 year ago.
The last time the car was at the mechanic which is about 2 weeks ago, the engine didn't tremble so they didn't scan it
Customer: replied 1 year ago.
I don't think though that this is a new thing. I think that I wasn't paying enough attention before. The engine trembles now a lot more often than 2 weeks ago.
Expert:  Fixitman replied 1 year ago.

It really sounds like a bad ground or connection problem from what you are telling me, unless there is build up that the Seafoam will clean out.

Customer: replied 1 year ago.
As soon as the seafoam is in I will bring the car back to the mechanic to clean the build up. But while it's there and might the seafoam not help, what can I tell them to check about the ground and connection?
Expert:  Fixitman replied 1 year ago.

The main thing is to check the ground connections from the engine and for the negative battery cable.

Customer: replied 1 year ago.
Ok thank you I'll let you know asap
Expert:  Fixitman replied 1 year ago.


Customer: replied 1 year ago.
They ran the seafoam through the engine. I do believe the engine runs smoother now but it didn't resolve the trembling part.
They've also checked the ground connections and the battery cables but didn't find anything out of order.
The auto scan gave the same computer code.
Expert:  Fixitman replied 1 year ago.

Are the code numbers exactly the same? Did they clear them after running the seafoam through it?

Customer: replied 1 year ago.
You're right. The error code changed to:
Ignition Coil C
Prim/Sec Circuit
Expert:  Fixitman replied 1 year ago.

Thank you. This code states that there is an issue with the #3 coil. If the coil is fine then it can be the connection at the coil. I have seen a lot of connector issues at the coil that can cause this also.

Customer: replied 1 year ago.
What can I say to the mechanic? If the problem is not the coil (maybe it's 1 of the coils that is already replaced). Which connection exactly should he check or which test should he do to find the problem?
Thank you
Expert:  Fixitman replied 1 year ago.

If that is the code that is still coming up then they need to check the connection at the #3 coil