DIY - Check/Replace your CPS Sensor

My truck is on the recall list. Bummer the dealership didn't mention that yesterday. They had to know.

Not sure of my build date, truck still at dealer.

I did not have any issues prior to this that come to mind.

 

I also ordered an extra sensor just to have with me.

 

Thanks for the update, and I hope they get you fixed up soon! There's a sticker on your driver's side door jamb (I think) that'll say the date.. mine was born 09/15. If it's not too much of a bother, could you let us know yours at some point?

Yeah it's strange that these sensors all of a sudden just stop reading the "defective" crank rotors. I would've expected some kind of lesser symptoms to show up before a complete shutdown (rough idle, intermittent power loss due to misfires, etc). Perhaps there's a threshold beyond which the ECM just can't (or won't) deal with errors from the CPS.

 

I definitely had some lesser symptoms such as steering pressure not getting enough power, bad bogging, etc., truck hasn't bogged since replacing the CPS. and steering is night and day

 

I think that some of these symptoms are being overlooked as "normal characteristics" or just firmware weirdness, when they could in fact be signs of impending CPS "failure". Damn, for the crank position signal to shit the bed badly enough to stop the truck completely, the original CPS hardware must have been right on the edge of proper detection of the out of spec crank rotor (too much anti-corrosion coating)when installed at the factory. I'm guessing that repeated heat soak and slight degradation of the sensor with time was enough to fuck things up but good.

 

Should pick up tomorrow afternoon and then driving 5 hours. Will check date and let you know.

 

Another working theory I have now... how many people have remarked on the incredible differences in power / performance by running different octane fuels (or E-free) when it is common knowledge that if your truck was designed for 87 (E10), there really shouldn't be a performance difference b/c any combustion gains are indeed not realized without a tune. I get it now - b/c I no longer feel a real performance impact to different fuels...

Well, prior to CPS I was one of those people who could throw a tank of 93 in there or e-free and feel an instant wooomph. For the past 8-9 tanks or so I've been using primarily BP mid grade and it was running pretty well post MAF + CPS but I just had to see how it would perform on ethanol free (89) again. This experience helps one (when looking at live data) see how this is SUPPOSED to work. Within a couple of miles, fuel trims adjusted (within a day even the long FT were staying within +-3% most times) with idling sitting right at 0 and a lamda of 1 (unless accel/decel/shifting then immediately corrects itself back to 1).

CPS plays such a big role.... with that thing sending bad data it's no wonder swapping fuels out made some people excited while others thought it was silly to run higher grade gas in an engine designed for 87.... but also explains why (in my case) it would degrade over time with different fuels if it couldn't get the data to advance the ignition timing properly.

"Used on engines with distributorless ignition systems, the CPS serves essentially the same purpose as the ignition pickup and trigger wheel in an electronic distributor. It generates a signal that the PCM needs to determine the position of the crankshaft and the number one cylinder. This information is necessary to control ignition timing and the operation of the fuel injectors. The signal from the crank sensor also tells the PCM how fast the engine is running (engine rpm) so ignition timing can be advanced or retarded as needed. On some engines, a separate camshaft position sensor is also used to help the PCM determine the correct firing order. The engine will not run without this sensor's input."

Anyhow, my thought for the day. Swapping my CPS has been the best thing I've done to my truck thus far.

 

And. Drumroll....
I drove to work in "D" today and never once gave a thought to the shifting (which normally was driven by the common bogging feeling.) I pressed pedal, downshift smoothly occurred when needed and it was even climbing small hills w/ ease w/o downshifting from 5th or 6th. Those gears may actually have a purpose after all...

21 MPG (w/ e-free) on a 16 mile trip combined stop/go and interstate. I've never put it in D since I've owned it without having the itch to throw it into "S" and/or ECT to get going....

I'm beginning to see why some folks on here with well-running trucks feel like the rest of us are lunatics and trolls.

 

Haha, I think those of us with problem trucks feel the same way about people with "no problems whatsoever". Its hard to believe they have no problems and I feel like they are either oblivious or trolling.

 

Yep... probably some of both on all sides, but if my truck had driven the way it has since I've replaced my CPS about the only thing I would be complaining about would be the vibrations in the steering wheel that could have been dampened better with a bit more care from Toyota. But in the grand scheme of all of the miserable drives I've had in this truck, that's a small drop in a pond. I hope it sticks. Loved driving my truck these last few days.

I'm going in tomorrow for my 15k (2k early but I'm about to take a long road trip) - just to get it on record, have them rotate my tires, and change front/rear diff since I'd consider 90% of my driving (stop/go in the city / steep mtn roads @ light offroad) in what 'Yota would consider "Severe" driving conditions. They ordered me one of the steering dampeners that they use on the driveline angle TSB (for which I am not qualified) to put on there just to see how/if it reduces the harmonic steering vibes. Will report back w/ a different thread if indeed doing the dampener alone makes for a smoother drive.

 

Were you on the recall list? Or did you just replace it.

 

I'm not on a single recall list... The only reason I did this was that I had some bad MAF issues - like sitting in hot traffic where I felt like i had to FLOOR it just to get the smallest acceleration. Keeping my OBD dash up as I do most trips these days, I noticed that my MAF was showing like 40g/s flow idling (should be around 3-5 when idling) and was further confirmed when I pulled into my garage at the house to smell the strong sulphur from the exhaust which I understand is indicative of a rich condition... it thought a ton more air was flowing in there and inputting fuel to match. So I just treated what was likely a symptom - cleaned the MAF, and it definitely fixed that immediate problem. MAF readings back in range and my cat actually cleaning up the exhaust again.

A member was doing some mental gymnastics and just off-hand said something along the lines of "I wonder if incorrect timing / injector data - which is highly dependent on good CPS data" could be causing mistimed detonation and thus slowly mucking up your MAF..." And honestly, after cleaning my MAF I kind of felt like I "found it" b/c it ran WAY better after cleaning. Still I was intrigued by the CPS comment and decided to order anyway, with no real expectations for changes in performance - more preventative. I've wasted $100 much more carelessly so it was worth the gamble...

You could feel it INSTANTLY when turning the ignition... it just started smoother, steering pressure felt "right" and the "normal" roughness just isn't there any more. So in my case, I too wasn't really expecting anything from the CPS swap, but it made it clear to me how crappy this was really running even when I thought it was at it's best.

I'm going to try not to continue to be to OCD about it for now, but I'm definitely concerned about long-term damage to my components. Particularly since I went through a couple of months of experimenting with all different fuel types to gauge impact on economy and driving experience. I never used anything lower than 87 so my hope is that even if it wasn't advancing the timing properly when I ran 93 or something, the worst it was doing was hurting my catalytic converter. But I suppose it would be wise to change spark plugs / coils at a minimum when I get the time.

 

This would be me, I have no idea what ppl are complaining about on this truck and its get up & go. It’s rarely that I’ll use ECT or even S mode now with 22k except for FuN & kicks. I did use it during break-in to bypass breaking\learning hiccups, and I rarely get less than 20mpg.
I get 22-24mpg average but mainly flat road with overpasses, no mountains. In city traffic or short trips (2-3miles) I’ll get 17mpg which is still much better than my previous Tundra.

Too bad Toyota doesn’t make a BOB like Ford does (to my knowledge) where we could view or pinpoint the direct sensor signals between all sensor(s) and ecm to catch the wave shape or form via a live lab scope and hopefully get a true perspective in order catch any abnormal anomalies that could aid in the capture of momentary glitches. The Maf sensor also comes to mind.
Instead, all we are left with is suspicions based past experiences.

As for the vibration there is a tsb see attachment that may warrant looking into if you haven’t already done so, that involves installing a steering damper and drive line angle.

All in all I’m glad you’ve made great success in getting to the root of your issues because I don’t think Toyota is going to replace any sensor unless they’re 99.9% sure it’s the problem, but hopefully this recall is their way of doing just that, so ppl can fully enjoy all the great technology in this great machine.

Cheers!

 

Well, I had the field tech inspect for the driveline angle (TSB) issue and he confirmed my driveline angles were within spec but even he was "curious" whether the dampener would help, the dealer just didn't have it in stock at the time so will see if that alone does dampen enough to be worth the effort.

 

If it doesn't have a damper in it now, I would hope putting one in will help.

Good luck
Cheers!

 

Where is this CPS sensor located and the cost of this part?

 

behind your front passenger wheel (Post #1 in thread is a great write-up)

$100, part number in post #21 above

 

this would be a cool feature. best I can tell, the codes that are thrown on these are more related to the individual sensor readings vs. a holistic look at the interchange between sensors and the data they feed each other. I could see the sensors sort of working against each other rather than together. I'd expect to see things like a rich A/F ratio driving some negative fuel trims and slowly adjusting the timing and injector volumes to eventually get fuel trims back close to 0 - something I can now see happening more harmoniously after I replaced my CPS. Before none of it was really making sense... it was just correcting, overcorrecting, confused all the time - but still each sensor (barely) within spec. So it was running "normal"

 

After my truck died on the freeway and exhibited the bad CPS symptoms I took it to the dealer but they couldn't reproduce the issue. I didn't want to get stranded in the Nevada desert, forced to drink my own urine like Bear Grills, so I opted to replace it myself. The old failed sensor had the hash marking along with my new sensor. But after 5k miles I haven't had another issue.

 

That's a little disturbing! Weren't the hashmarks placed on the new, improved sensor to distinguish them from the bad, old ones? I wonder how we tell the good hashmarks from the faulty ones now?