rallyxb

Hello All,

I have a 2004 xB automatic, that has been running perfect up until 62K.
The only engine mod is a Toyota TRD free flow air filter, which I recently cleaned & re-oiled. I have used this TRD filter since the xB was new and it has increased MPG and performance.

THE PROBLEM:
The next day the: Check Engine, VSC, Trac Off and Blue Low Coolant Temp warning lights all came on. The fan started to cycle on/off as if the engine was overheating and when I slowed down the xB downshifted to 3rd as if the engine was not warmed up, which is a feature in automatics to warm the engine quicker.

TROUBLESHOOTING:
I was able to get the box home and I gave it the once over checking for any loose wires or plugs that may have been accidentally bumped when I changed the air filter. I found nothing out of sorts, so I checked the airflow sensor, which was also clean.
I checked the posts on ScionLife and found a few similar threads, so I took the xB to the nearest Auto-Zone to have the trouble codes read.
The guy pulled up a P0118 (engine coolant temperature circuit high input.)
On the way home I picked up my own ODB II scan tool from Harbor Freight and double checked it when I got home. I got the same reading and used the scan tool clear the trouble code and drove the car briefly.
The same problem and error code happened again.
I found a website that has pages out of the 2004 Scion xB repair manual (shop manual?) and tried to diagnose the problem further, but cannot. The PDF file is here:
http://www.myjdmphoenix.com/images/0...emperature.pdf

QUESTIONS:
1. What would cause the: Check Engine, VSC, Trac Off and Blue Low Coolant Temp warning lights to all come on?
2. Where is the Engine Coolant Temperature Sensor located?
3. How often or how many miles should the radiator coolant be changed?
4. Could (original from 2004) radiator fluid have caused this problem?
4. Is this problem covered by warranty?

Thanks in advance for all your help.
- RallyxB

x2_da_b

is that the only thing you did to the xb? well if so then its probably the sensor for the intake.
the only time i had tose lights on was when i changed my tail lights an i didn't put in one of the bulbs correctly.
im no mechanic but thats my guess.. the sensor. you can bring it to the dealer but they charge like 90 an hour...rip off

rallyxb

Thanks for the advice.
Aside from NGK iridium spark plugs at 15K, which have made the xB run better, the TRD air filter is the only engine mod. I even switched back the the paper OEM air filter until I get this issue figured out.

By the way, does anyone know where the Engine Coolant Temperature Sensor is located? In the repair manual PDF I found (see above) it has steps on checking the sensor.

rallyxb

Forgot to mention... aside from the cooling fan kicking on/off ,the xB still runs good and is responsive. The weird downshifting thing only happens when the blue coolant light is on and I am just starting off from a stop light. This cold coolant light is intermittent.
Also... I have been reading other related posts here and a lot of people mention the MAF sensor.
I wonder if it's possible it got a little oil on it when the TRD air filter was re-oiled?
Can this MAF sensor be cleaned with brake cleaner?

rallyxb

Hmm... I guess the group is busy with other posts or was left speechless...


OK crew, I finally figured it out and fixed the problem!
I learned a lot in the process, so I thought I would share with my ScionLife comrades what I learned, in case anyone else has this issue again.

POSSIBLE CAUSES:
* Loose or broken wire, or loose connector to sensors
* Defective Coolant Temperature Sensor or dirty connector
* Dirty MAF (mass air flow) sensor from: dirt, dust, or oil from TRD air filter, or dirty connector
* Possible ECM (computer) glitch


THE FIX:
1. Disconnected the battery first.
2. Turned ignition to ON, to help discharge circuits and clear trouble codes.
3. Check all the wires for kinks and breaks.
4. Unplugged the Coolant Temp and MAF sensor connectors and made sure they were clean, then plugged them back in.
5. Removed the TRD (oiled) air filter and replaced it with the OEM paper filter.
6. Removed the MAF sensor, noticed there was a fuzzy brown dust on the sensor elements, and carefully cleaned it with the MAF cleaner spray. Let it dry for 10 minutes.
7. Reinstalled MAF sensor
8. Turned ignition to OFF and removed key
9. Reconnected the battery
10. Start car, let idle for 5 minutes, then drove it... with no problems! Woo Hoo!


REFERENCES:
* Location of Coolant Temperature Sensor: http://i225.photobucket.com/albums/d...01/coolant.jpg
* Original Coolant Temperature Sensor posts: http://www.clubxb.com/forums/f28/coo...ges-25995.htmF
* How to clean MAF in an xB: http://www.clubxb.com/forums/f14/diy...ing-28027.html
* All about the MAF sensor: http://www.teamswift.net/viewtopic.php?t=7438
* How to clean the MAF: http://www.popularmechanics.com/auto...o/3297276.html
* MAF cleaner spray: http://www.autobarn.net/maairflsecl1...te=google_base
* ODB II scan tool from Harbor Freight: http://www.harborfreight.com/cpi/cta...emnumber=94169
* 2004 xB Repair Manual, SFI systems (P0188 code ) troubleshooting spec: http://www.myjdmphoenix.com/images/0...emperature.pdf

CONCLUSION:
I took the xB to my trusted local mechanic, to have him double check for the problem and also change the radiator coolant. He said his scan tool could find no trouble codes, and that the engine was running great. He did mention that he has seen MAF sensor problems on cars before that have been using the "oiled" reusable air filters. He recommends using a paper filter. If you must use a reusable filter, be very careful not to over oil the filter and also to clean the MAF every time you change your oil.

rallyxb

I spoke too soon... after about 250 miles of trouble free driving the problem has come back and the Check Engine, VSC, Trac Off warning lights are all on again.

The weird thing is now my ODB II scan tool can't connect with the cars computer to get the trouble codes and shows a "Link Error".

The car is still running good, but is a little sluggish.

Is it still safe to drive?
Any ideas what's wrong?

rallyxb

Now the Blue Coolant light (low coolant temp indicator) is coming on intermittently AGAIN with the cooling fan running as if the engine is overheating.

I *just* had the radiator fluid flushed and refilled after this problem happened the FIRST time, so I know its not the coolant or the engine over heating.

Is it a sensor?
If so what?

rallyxb

From reading other posts here it seems like the problem could be caused by one or more of the following:

1. Brake pads <2% (may trigger VSC and Trac Off)

2. EVAP (charcoal canister full) and/or black box at rear of car may have a loose or cracked hose. (may trigger check engine)

3. Broken ground wire from engine to frame, especially under the car. (may trigger check engine)

4. CAM gear sensor (may trigger check engine)

5. Wheel speed sensors (may trigger VSC and Trac Off)

6. Bad ECM aka: Electronic Control Module (may trigger all)

Any ideas or suggestions would be appreciated.
Thanks!

itlstl13

check ur MAF sensor (its the one that goes into your air intake) it may have gotten dirty, try cleaning it, then reset your ecu and let your car idle for about 10-15 mins...

Also get your CEL codes read as well.

sbkob2447

iTrader: (1)

That happened to me too... my VSC, trac off and check engine lights came on at the same time and I flipped out. I replaced the o2 sensor and that didn't do the trick. I'm guessing it's my MAF because i have a K&N intake in there. It's so annoying - I never tried cleaning it though. For the last 6 months the three lights will come on like once a week, stay on for a day, and then disappear.

rallyxb

Thanks for the suggestions!

I already cleaned the MAF sensor (see above posts) but I will check it and clean it again just to make sure.

I am resetting the ECM by disconnecting the battery (both posts) before I clean the MAF, then waiting about 5 minutes.

Any other suggestions today would be greatly appreciated, as I have an appointment with the dealer to take it in at 10:30 (EST).

Thanks!

jct

this looks like a tweeter thead from the looks of it

rallyxb

I have tried all the tricks and alas, to no avail. I checked the brake pads, speed sensors, ground wires, and MAF sensor (again) but nothing looks out of order or seems broken.

So.. It's off to ye' old Toyota dealership for repairs.

Lets hope they can fix it for a reasonable price.

rallyxb

Just got a call from the dealer. It's a faulty: engine temperature coolant sensor.
They have to order the part, but it wont be in till Friday.
They want $165 for parts and labor.

I can fix it myself if I figure out what "name" of sensor I need.
I see 2 at the Auto Zone website:

For a 2004 Scion xB 1.5L MFI DOHC 16V 4cyl:

Duralast/Coolant Temperature Sensor
Part Number: SU4300
Application: Marked "Denso"
$42.99

Duralast/Coolant Temperature Sensor
Part Number: SU4302
Application: Marked "NTC"
$51.99


So... which one do I need?

rallyxb

Any ideas on which part from the above post?

rallyxb

I *just* got the car back and took out the part out (more on that later)

Here is the info written on the side of the Coolant Temperature Sensor...

89422
16010

Which matches this from:
www.napaonline.com

OEM # 89422-16010
Item # DEM TS10183

$85.49

rallyxb

UPDATE...

I found the same part cheaper at Auto Zone:

www.autozone.com
Duralast/Coolant Temperature Sensor
Part Number: SU4300
Application: Marked "Denso"
Availability: Normally stocked at your local store.
Warranty: 2 YR
$42.99

I removed the original Coolant Temperature Sensor and confirmed that the OEM number is: 89422-16010.
When I called the Auto Zone, they cross-checked it to match the part as:
OEM # 89422-16010 = Denso # SU4300

HOW TO REMOVE THE COOLANT TEMP SENSOR
1. Jack drivers front corner up about 18 inches (to keep coolant from leaking out)
2. Disconnect battery
3. Remove Engine Cover (plastic)
4. Disconnect air intake hoses
5. Disconnect plugs to MAF and air box
6. Remove air intake box
7. Disconnect plug to Coolant Temperature Sensor
8. With a wrench, remove Coolant Temperature Sensor (it's like a big spark plug)

NOTE: The Coolant Temperature Sensor will come out a lot easier when the engine is hot (metal expands remember?)
It took 25 minutes to remove the Coolant Temperature Sensor.

Reinstall was in reverse order.
Remember to re-use your brass washer from the original sensor.
It took me about 15 minutes to reinstall it.

After I reconnected the battery, I started the xB and let it idle for 5 minutes (so the computer could re-learn) then drove it.
All warning lights are out and it runs great!
Woo Hoo!

:D