[bearskin]

Issue: speedo works intermittently, will jump around or go to zero. No check engine light. No other apparent issues with instrument panel. Trip meter displays "Er SP" which I understand is a DTC for "ABSCM/VDCCM information and vehicle speed pulse malfunction".

I don't have any codes yet but plan to do this tonight according to description at: http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/19053-05-09-how-read-diagnostic-trouble-codes-dtcs.html.

However, I understand that it could be one or a combination of the sensor, modules, harness or the actual meter (thanks to ron917 at: http://www.subaruoutback.org/forums/66-problems-maintenance/15874-speedo-intermitantly-quits.html).

In an attempt to check the connections on the back of the instrument panel I removed the instrument panel (thanks to instructions from JimBNH at: http://www.subaruoutback.org/forums/66-problems-maintenance/7872-taking-apart-dash-instrument-cluster.html). However, I could not pull the instrument panel out far enough to get access to the back of it and I did not want to pull too hard thinking that I may inadvertently disconnect or break something.

Apologies for the long preamble. My question is: Are there detailed instructions somewhere in this forum or elsewhere that can show me how to check speedometer connection, speed pulse sensor, ABS/VDC modules and the harness for proper function? I found plenty of info, threads, youtube vids for earlier generations but not much for the 05-09 generation.

Thanks in advance for any info you can provide!

 

[plain OM]

The ERxx indication in the trip meter is indicating a communications problem in the car's LAN, with the "SP" pointing to wheel speed information. It's usually a loss of data transfer between various modules, such as engine, transmission and ABS/VDC, and not a fault in a particular component such as a sensor.

Sometimes it's a random situation that occurs on boot-up, with the "ErXX" showing in the trip meter immediately, even though no symptoms have been noticed. This is usually corrected by turning the ignition Off and starting again. (I'm not sure about this, but I believe that if the key is turned from Off to ACC to On and to Start without pausing at ON to allow the gauges to sweep and modules to boot-up fully -- indicated by some warning lights going out -- this type of malfunction is more likely.)

In the case of incorrect wheel speed data, the vehicle speed information that is processed in the control modules and conveyed, via the LAN, to the speedometer microprocessor could be problematic, leading to the strange speedometer indication.

There are trouble codes related to the LAN; they're identified as B#### or U####. I don't think the "How to read diagnostic trouble codes . . ." technique will read these, but it's worth a try. (It should, however, show codes for the ABS/VDC. If a wheel speed sensor is indicated, that could be the root cause.) Otherwise, the Subaru Select Monitor (dealer) might be needed.

Let us know what you find.

 

[bearskin]

Thanks plain OM! I did the DTC check and got a "C0108". I see in your response to SubaCool at http://www.subaruoutback.org/forums/66-problems-maintenance/21229-cel-er-55-a.html that C0108 indicates "abnormal front left wheel speed sensor signal".

So, I expect my first course of action would be to make sure this sensor is free of dirt etc? I expect that if general inspection/clean up doesn't work then I am just replacing? Any other suggestions?

Wondering...in case you know...I have access to a 2005 FSM but could not find any information relating to DTC C0108. I was hoping for full description/procedure as provided for all the P#### codes but did not see anything. Did I miss it or is it just not there?

Thanks again!

 

[plain OM]

The C### DTCs are ABS. If you have the complete 2005 for your car, the related diagnostic section is in the Chassis volume, section on "ABS (Diagnostics)", sub-section Diagnostics Procedure with Diagnostic Trouble Code (DTC)". The last section contains pages for each of the DTCs (in order) with the diagnostic (troubleshooting) procedures. The page for C0108 is ABS(diag)-41, or thereabouts (different versions of the FSM,due to updating/correcting can have different pagination).

That DTC is not indicating a failure, such as a short or open circuit; rather, it's indicating that the signal being received is not normal. It could be "noisy", or the wrong waveform, which prevents the ABS control module from getting a good reading of the wheel speed.

It's interesting that you're not getting an ABS warning light with that code. I wonder if that could be an older code (that is, no longer an active problem, but stored in memory).

Have you changed a wheel bearing (hub assembly) recently? The wheel sensor detects a signal from a magnetic strip on the back of the hub. Some members have reported problems related to the wheel sensor when using aftermarket hubs. In some cases, the cause of this could be the hub, but in others it could be anything that upsets the magnetism of the new hub's magnetic strip, including magnetic tools, or banging on the hub.

 

[bearskin]

Thanks again. No, I haven't changed a wheel bearing or hub assembly and I haven't been messing around with anything in that area.

No ABS warning light but I'm not sure it's an older code since I still have the issue with my speedo.

Based on my read of the Diagnostic Procedure on ABS(diag)-42, since I have the speedo issue I think I'm going right to step 7 to check the sensor itself for proper installation and that it is free from dirt/damage. If that doesn't work I think I'm off to the dealer since I don't have a Subaru Select Monitor or an oscilloscope.

 

[plain OM]

Sounds like a plan. Let us know what you find . . .

 

[tdelker]

Another 'out there' possibility is voltage. If you battery is bad it could be pulling down overall voltage, or if you alternator is struggling. This can set off some strange codes. It's a somewhat common problem to look for when you have a number of DTC codes, but haven't heard about it on the ABS/speedo side.

 

[bearskin]

Thanks tdelker - I will def check this out if plan A doesn't work.

Will report back after I'm able to do the work this weekend.

 

[bearskin]

Well the good news is the problem seems to be gone. The bad news is I don't know why. I inspected the sensor and harness and didn't see anything notable. However, the speedo started working consistently and the "Er SP" message disappeared before I did the inspection so I don't know what caused it to work again. My best guess is that the wet, mushy, sloppy mess of leaves on our local roads, which has been collecting in everybody's wheel wells here, may have interfered with the proper function of the sensor.

Hopefully this story is over but if not I will post it.

 

[dean]

problems are: 1-"ER sp code on the trip odometer 2-and tire pressure sensor dash light is on and 3-also the speedometer doesnt work 4- odometer doesnt work.

its on a 2006 tribeca with the 3 liter -6cylinder.
problem started after a 2 .5 inch rain and I left the sunroom open and a window.

I have pulled all the carpet, dried the floors and sprayed the two 12 pin connectors, car has sat in the heat for 2 weeks...no luck ...

reset the CEL by grounding positive cable

any advice?

thanks
Tribecadean ( Sb9t forum)