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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4605
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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I have an 1989 4runner 3vze 4x4 automatic with the usual temp

Customer Question

I have an 1989 4runner 3vze 4x4 automatic with the usual temp sensor issues and the code 52 . I have replaced the knock sensor and harness. I want to know which sensors talk to what ecm/tcm, and what was the fix that Toyota engineered to fix the sensor Pod problems. My 4runner continues to show code 52 after 3 to 5 days of clearing the code and the overdrive will not stay engaged. My engine temp gauge in the dash typically shows low engine temp.
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Toyota. The Toyota Mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: Yes
JA: Great! What have you tried so far?
Customer: New sensors and disconnected the ecm to check for bad conections
JA: Is there anything else important you think the Toyota Mechanic should know about your Toyota?
Customer: If I let the truck worm up in the drive way, it will shift very smoothly and the overdrive will work until I drive , which will make the engine tempo drop.then it will shift out of overdrive. if I don't worm it up in the drive, then it will shift hard until the engine warms up. the overdrive will not work
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Toyota Mechanic about your situation and then connect you two.
Submitted: 7 months ago.
Category: Toyota
Expert:  Toyota Service replied 7 months ago.
Hello. Welcome to Just Answer. Please allow me to assist you. The code 52 Knock sensor has nothing to do with the overdrive being inoperative. Your OD will not stay engaged because your coolant temperature is too low. The overdrive is prevented from working if the coolant temperature is below 177 degrees F.
Expert:  Toyota Service replied 7 months ago.
The code 52, assuming your knock sensor is a genuine Toyota sensor, and the harness is also genuine, the issue may be a stretched timing belt. If the belt is causing the cams to be out of time, you will get knock. There may be nothing wrong anyplace engine wise. just the belt may be stretched.
Expert:  Toyota Service replied 7 months ago.
I would recommend a new timing belt and a new thermostat to cure these issues.
Expert:  Toyota Service replied 7 months ago.
Please confirm that you have received my input. If you have any questions, please feel free to ask. Thanks.
Customer: replied 7 months ago.
I just installed a new timing belt all pulleys tensioners, water pump, thermostat, oem knock sensor and harness, along with many hoses and two of the sensors on the rear of the engine.
Customer: replied 7 months ago.
Will I not be getting anymore answers? I already new everything that you told me. I was hoping for a fix for the issues with the sensor pod on the rear of the engine. I know Toyota had a problem with this not filling with coolant properly and as a result the sensors did not report the correct temperature. I have seen a later version of the pod with a hose in the middle, was this their fix?
Expert:  Toyota Service replied 7 months ago.
That has nothing to do with the trans shifting. You need over 177 degrees of coolant temperature to allow the OD to engage.
Expert:  Toyota Service replied 7 months ago.
The coolant temperature is measured by the senor on the front of the engine.
Expert:  Toyota Service replied 7 months ago.
If your engine temp is low, your coolant temp is low.If your coolant temp is low, you do not get shifting into OD.Additionally, if the coolant temp is too low, you can get pinging (knocking).
Customer: replied 7 months ago.
This is a 1989 3vz, no sensors on the front of the engine. and I know the engine must be at 177 degrees or higher for the trans to shift into overdrive and to lock the converter. is it a sensor to the ECM that tells the trans to shift or a separate sensor to the TCM? and which one is it, (part number please)
Expert:  Toyota Service replied 7 months ago.
The coolant temp sensor for the fuel injection is the sensor for the OD
Expert:  Toyota Service replied 7 months ago.
Clearly you have an temperature issue if the temp gauge reads low.
Customer: replied 7 months ago.
Thank you, ***** ***** know a part number? also have you not heard of the issue with the sensor placement at the top rear of the engine? I do not believe that my engine is not at proper temperature, I think the sensors aren't actually in the liquid coolant
Expert:  Toyota Service replied 7 months ago.
89422-20010We have had many 89 v6 4Runners in our shop over the last 20 years; I do not recall ever having to address a 'sensor pod' issue.
Customer: replied 7 months ago.
Do you think switching to a 190 degree thermostat would fix the shifting issue? I have the factory recommended 180degree.I guess I need to get or borrow a laser temperature reader and find out the actual temperature of my engine.
Expert:  Toyota Service replied 7 months ago.
Yes, a 192 degree (genuine Toyota) and the cooling system properly bled should fix the shifting issue.
Customer: replied 7 months ago.
Thank you, ***** ***** give it a try. the forums are full of discussion about my issues, and I thought by now there would be an absolute fix. I talked to a tech who worked for Toyota and he said there was indeed a recall on the overdrive issue and it was very hush hush. they had one highly paid tech who repaired them.
Expert:  Toyota Service replied 7 months ago.
You are very welcome; that is News to me on that aspect. Never had any issues like that; I have been with Toyota since 1994
Expert:  Toyota Service replied 7 months ago.
A positive rating for my input would be greatly appreciated.

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