Troubleshooting my cruise control

For the past few years the cruise control on my manual V6 '05 Tacoma will not turn on (no green CRUISE light in the dashboard). After doing some research I have seen that the most likely component is either the clock spring or the column stock. What can I do to determine which one is the culprit?

Additionally, I have a P0500 speed sensor code that according to O'reily could have multiple causes. The cruise failure and the code did not pop at the same time but I am still concerned that they may be related.

Any help would be greatly appreciated!

 

Well, first place to start is looking at fuses.
-P0500 will cause cruise to not work also, however it sounds like that wasn't the original cause.
-Could be your brake pedal position sensor or any of the wiring (including trailer brake wiring), not likely though. If you have a scan tool or bluetooth dongle scanner that connect to your phone you can check that switch is operational, as well as many other switches. I would recommend one since you can see if a switch is activated when depressing it, if a switch is not recognized then chase that area. Usually if your brake lights are working fine then the brake pedal position sensor is working right.
-You can check for power at the switch and before the clock spring as well by removing the airbag before getting too deep into replacing the clock spring. Also ohm out the switch





-The system can also stop working if there is issues with the throttle body.
-The PRNDL/shifter position switch



There are many things that can cause cruise control to not work....but many times it's something simple.

Below is the wiring diagrams.....proceed at your own skill level. haha

 

Great info there

I’d start with the P0500 code.
Since the Auto Cancel Feature will turn off the Cruise Control if the speed signal is faulty

 

I disconnected the battery to pull the airbag and then tested the switch. Got the correct ohms for everything except for "Off" position. It just read 0. Not sure what that means. However when I put everything back together and reconnected the battery the CEL went away. Think I might buy the bluetooth dongle to try and do some diagnostics. Any recommendations on the best buy?

 

Just depends on what type of device you have. If you have iPhone you need a WiFi dongle, Android uses bluetooth. I don't know that are any that are considered the best, they all operate the same way. The app for your device makes the difference. So you just want to make sure the dongle is compatible with the app you want to use. I use "Car Scanner Pro" and it seems to do everything I need to on my iPhone or iPad.

 

Check your VIN on toyota.com, some of the 2nd gens had faulty clocksprings..mine was done as a recall. I don't have cruise control but this might help

 

does your speedometer on your instrument cluster work? You could have a fault speed sensor. If you have the P0500 code and your speedo is working, your ECM is not getting the correct speed signal sent from the instrument cluster. Speed is the feedback required for cruise to work, so without a proper feedback signal I would imagine the system will inhibit cruise control from being attempted.

 

A bit of an update... Submitted and went to Toyota for a diagnostic. Not only did the P0500 pop up on their system but also C0205 and C1236 from the ABS ECU which derive from debris causing a malfunction with the FL speed sensor. The dealer said that I would need a wheel bearing replacement and a new speed sensor to fix those codes which the quoted at ~$3000... not a chance. I replaced it all my self (the wheel bearing was shredded and did need to be replaced) but still I have the P0500 code and no cruise control. I thought it could be a harness issue from the sensor to the ABS ECU but when I unplugged the harness it drove an ABS light and went away when I plugged it back in. So I ask you all this:

1. Is there a way to pull the ABS ECU codes by myself to see if the C0205 and C1236 codes are still there?
2. I bought a multimeter but am, for the most part, electrically illiterate. Was looking for some info on how to utilize it to see if the cluster or the ECM is bad.

Any other ideas on how to troubleshoot the system would be greatly appreciated.

 

I can’t help with #2.
But hopefully this helps with #1

https://www.tacomaworld.com/threads/abs-and-traction-control-light-on.730277/#post-26011288

 

Since you mentioned you have a Mulitmeter here are some checks you can run.

One of the biggest things to check for when looking over specific wheel speed sensors is the sensor condition. When inspecting the speed sensor and ABS ring on the wheel bearing it is important to look for any grease, debris, cracks or worn areas on the sensor. Also make sure the base of the sensor where it bolts up is flat and seated properly. If it is not sitting flat on the hub and is angled a little bit it will change the air gap between the face of the sensor and the ABS ring, that air gap is imperative to how the sensor picks up wheel speed from the ABS ring. Since you noted having to replace the wheel bearing, the ABS ring may have (if the bearing was really bad and allowed for a lot of play) contacted the face of the sensor which would damage the sensor and make it inoperable. If you attempt to remove the sensor, be prepared to buy a new one. They are generally pretty difficult to remove after 15 years! Even if the OHM readings are correct according to the specs below, if it has any damage it must be replaced because it will be getting false readings due to a compromised sensor. It's actually pretty impressive that these systems require such fine tolerances to be met, yet they last a long time, take a ton of abuse and can do it in a mass produced fashion.

I just did screen shots for this, sorry if it's difficult to read. The pinout for the testing looks confusing when looking at the connector view (in step 1) and where to place your meter leads. Don't look at it too deep. Just set your meter to the resistance/ohm setting and put your test lead on the 2 pins. If the sensor reads below 1 ohm your good, assuming the above is good. When checking the "Body Ground" specified in part 2 of step 1, just use the hub when checking the sensor (since it would ground to the hub before anything else) and if you need to check the ECU connector then choose a ground that is close. If there is continuity when checking the sensor to the hub this would indicate the sensor likely is corroded or cracked and grounding to the hub, which would make the previous 1 ohm reading invalid at that point because the sensor is bad. When using the hub as a ground you will likely have to scrape off some corrosion to get a good ground surface, you want bare metal, just use corner of a flat screwdriver to scrape a small spot clean.

 

Forgot to mention, the P0500 is tied to the Vehicle Speed Sensor (VSS). The ECU, TCU, ABS, Cruise Control, Speedometer and other computers and modules. When one sensor (like an ABS sensor) is bad it will throw this code and generally disables many other functions. Like traction control, stability control, cruise, speedometer, can cause abnormal transmission characteristics and sometimes Yaw/Vehicle Tip sensor function. In other words, once you find the issue, this code will go away.

 

Alright! Its been a long day but I have finally fixed it. It seems there were two problems compounding each other....

First was the ABS ECU. Even though I replaced the sensor and bearing the ABS codes were still held in the system. Thanks to TnShooter for providing this info (https://www.tacomaworld.com/threads/abs-light-and-vsc-light-both-came-on.699123/#post-24756496) I was able to clear the ABS codes which in turn cleared the P0500 code. I then ran continuity checks on all the wheel speed wiring as suggested by TacoFergie and everything was good but still no CRUISE light.

At this point I wanted to test the spiral cable (clocks spring) as I know this is a common problem. Besides having the P0500 light I didn't think this was the problem at first because I had no issue with the airbag that also runs through the spiral cable. Once I had the airbag I tested for continuity... There is two places to do this. The first is the cable that connects from the CC stalk to the clockspring. This check fine. I then wanted to check the spiral cable itself. At the top front there is a three-pin connector (top right in my picture). The top pin is for the horn and the bottom two are for the CC. To access the other end of the wire I removed the shroud from around the steering column. Behind the wheel at the bottom are two connectors. A yellow one for the airbag and a black one for the CC and horn. Unplugged the black one and checked the three pins and low and behold one of them was dead.



Just be sure it was the clockspring I wired a replacement to the switch before pulling the old one and it worked. Thanks for all the help everyone and hopefully this thread will help someone in the future. If anyone has any questions fire away

 

ANY Codes or issues & the Cruise will not work

the brake pedal has an adjustment at the back..............if thats out it wont let cruise reset

 

Congrats man!!! I bet thats a relief to have it done and over with! Luckily you didn't have the dealer do the repair, chances are they would not have gone through the wiring checkouts as thoroughly as you did and would likely throw parts at it. Which is common these days due newer techs trying to make time on flat rate and sadly there is a shortage of give a sh*t nowadays.

@TnShooter, that's an awesome link you posted! I did not know that it would not reset itself after repair, even just a speed sensor. I'm used to most vehicles ABS lights resetting themselves after going above a specified speed.

 

Thanks man but unfortunately the CEL is back and I have figured out why. Both before I replaced the bearing and since the new bearing is installed, every time I pull the speed sensor it is covered in grease causing the signal to be degraded. I have no idea where all this grease is coming from especially from a new bearing... Could it be coming from the CV joint? Regardless I would like to find a borescope and stick it in the sensor hole so that I can look in without having to remove the bearing again.

 

Grease on the sensor will not affect the signal as long as theres no metal fillings in it.