Cruise Control not engaging (Not Clock Spring or CC switch)

What appears to be an outlier problem with Cruise Control...(Codes: B2282 and B1271)

Background: just picked up an 08 with 140K miles Touring model (a true Touring model). Got it running well and took it out on the highway to find out the CC doesn't engage. I have worked on many 2nd Gens in the last 10 years and probably 95% of the time CC is fixed by replacing the Clock spring and/or the CC switch itself, however in this case, neither made any difference.

I used Techstream and opened up the Cruise Control ECU area and looked at the Live Data portal (see picture). I compared the data between this non-working car and a known working 06 that I have and this is what I found:

1) All commands from the CC switch are being recognized by the live data parameters. Ex: when I turn the CC on or off or set/accelerate by using the CC switch I see the values change accordingly in the live data. The working 06 does the same thing.

2) Only difference is that the first parameter (CCS Vehicle Spd) which is obviously recording vehicle speed in mph on bad car is not behaving correctly. I starts recording accurate speed under 10 mph but then as I go over 10 mph (roughly) it gives up and starts to fall back to zero.

3) The good car shows accurate speed and once I get to 25 mph allows me to set the CC and at that moment I see parameter #2 (CCS Mem Vehicle Spd) show the same value as CCS Vehicle Spd and the CC is engaged.

4) Based on that, I believe the CC won't engage on the bad car because the ECU doesn't know how fast the car is going.

5) I am assuming this is coming from the Combination Meter or what is called the Power Supply Control Module (part # 89670-47010) and so I purchased a used one on Ebay. I have never had to replace this on all the 2nd gen priuses I've touched (over 100) so I'm kind of skeptical that it's bad.

6) Combination Meter--I have done the capacitor replacement on at least 20 2nd gens, so I will definitely be doing this, although so far, I haven't seen it act up.

Here were the codes that were logged on Techstream which lead me to conclude it has to do with the Combo meter or the PSC module: B2282 (Power Source Control) and B1271 (Gateway)

I have looked all over PriusChat for any posts related to this and found none--I'm looking forward to hearing from all the great PriusChat experts on here! TIA!

 

Thanks, appreciate the feedback. I'm definitely going to do the combination meter repair. While I'm in there I'm going to look for this power control module and replace it in between the two hopefully the cruise control will start working again.

 

Ok gotcha I'll do the combo meter first and chime back afterwards

 

The part is only costing me $20. And it's easy to get to once the dash is disassembled. Once it arrives I'll fix the CM and replace the PSCM and see if the CC is happy. I've never seen the PSCM go bad on a prius so I doubt the pulled part has a problem but we'll see...

 

Update: fixing capacitor on combination meter made no difference. Waiting for the PSCM to arrive...

 

Result:

Replaced power control module and no change. Cruise control still behaving the same way and will not engage. Didn't do a deep dive on testing wiring and voltage/ resistance per the wiring toyota however all of the wiring and harnesses looked completely normal. No corrosion or anything out of place. At a loss. Only thing I can think of is that the combination meter has a faulty soldering point, but I'm not about to get a junkyard combination meter to try that theory. So for now will just deal with no cruise control.

 

Yes, still have B2282. CM working fine.

 

Here's the workup for B2282:

DTC B2282 VEHICLE SPEED SIGNAL MALFUNCTION (CABLE ... https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bi6/cib2282.pdf

 

Yes and yes

 

Final Outcome:

Matt at Texas hybrids is very helpful. I had experimented with the setup of the 05 combination meter in the 08 dash assembly a few days ago and was freaked out by all the weird lights on the dashboard so I did not test drive the car in that configuration. Well, evidently I was only a 30 second test drive away from proving that the combination meter was the problem all along to my cruise control not working. I redid the experiment today with that setup while taking the test drive with wonky lights (cruise control light was now the front defrost light) AND...

The cruise control worked perfectly!!!!! Very elated! Now I'm going to send my newly diagnosed defective 08 cluster to Matt for his Museum and he's going to send me a workable 06 to 09 cluster with the exact same miles.

This has been a two or three month ordeal since I bought this car and my wife has a bad back and really needs Cruise control. It started with the obvious things to look into like the clock spring in the actual CC switch and then I replaced the power supply control module near the combination meter. The only remaining areas where the harnesses themselves and the combination meter.

This is clearly a very outlier defect because I have not found anybody online that's had this exact scenario. Because the capacitor issue is incredibly common, it overshadows any other issues with the combination meter which are obviously incredibly rare. So hopefully some unlucky soul who has this exact same problem will find this to be a shortcut that I didn't have 3 months ago.

Cheers