Check Engine Light - Speed Sensor Fault

Tiny
JOHNSERB
  • MEMBER
  • FORD TAURUS
1998 Taurus 3.0L 4V DOHC engine 92K miles

Check engine light came on and Autozone read code. They indicated speed sensor is bad. Can not detect any common symptoms from a bad speed sensor. Speedometer is working, transmission shifts are smooth and lock-up torque conv is engaging. No black smoke from exhaust or engine pinging. Did not check anti-lock brakes.

Not sure where to check next. A quick review of some other Taurus/speed sensor posts indicates it is another "fun" job.

I have the Ford 1997 Taurus service manual (about 3" thick) but, hasn't been much help yet.

PS: Recently had alternator replaced. What a "fun" job that was! Can't see where something from that repair could have caused this, but light came on one day after repair completed.
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Sunday, November 25th, 2007 AT 3:02 PM

7 Replies

Tiny
RASMATAZ
  • MEMBER
Do you still have the VSS code?

Its located at the tranny Have you open and inspect it or the wiring.
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Monday, November 26th, 2007 AT 5:02 AM
Tiny
JOHNSERB
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"Do you still have the VSS code? "

No, the guy at Autozone did not give me the number, just the verbal description. I can try to get it read again, or buy a code reader.

"Its located at the tranny Have you open and inspect it or the wiring."

I've tried to find it from the top and below while car on ramps. All electrical connections going to tranny seem to be intact. I do have a picture of sensor now, and approx location, so will recheck.
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Monday, November 26th, 2007 AT 5:39 AM
Tiny
RASMATAZ
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My Q is-Is the check engine light still On or OFF?
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Monday, November 26th, 2007 AT 5:42 AM
Tiny
JOHNSERB
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"My Q is-Is the check engine light still On or OFF?"

It is still ON. I did not ask the guy at Autozone to reset it. It was my understanding (maybe wrong) that it will not clear on its own. The car has only been driven about 40 miles since the light came on. Ie to and from Autozone.
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Monday, November 26th, 2007 AT 6:05 AM
Tiny
RASMATAZ
  • MEMBER
It takes a scantool to clear the code go back to autozone have them erase it. If it comes back up-you got a problem with the VSS/wiring or the computer.
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Monday, November 26th, 2007 AT 9:57 AM
Tiny
JOHNSERB
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Thanks. I will be busy for most of this week, and hope to get back to it on the weekend. I ordered an Actron CP9180 which should be here by then, too. I will post back on results.
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Monday, November 26th, 2007 AT 12:34 PM
Tiny
JOHNSERB
  • MEMBER
Received code reader on Friday. Read code today. I am only getting an enhanced code of P1518 - Intake Manifold Runner Stuck Open Bank1. There were no pending codes. Autozone did not erase code, so don't know why my reader is providing different data. They used an Actron scanner, but it appeared to be a different model.

Erased code, warmed up engine, and drove for 5 miles. Check engine light did not come back on. I will research code further, and monitor for re-occurrance.

Search Info: http://autorepair.about.com/library/faqs/bl660e.htm

The intake manifold has what is called Intake Manifold Runner Control (IMRC).

The air induction system improves engine performance by using the intake manifold runner control (IMRC) assemblies as follows:

The intake manifold has two runners per cylinder, feeding each of the intake parts in the cylinder heads.
The IMRC assemblies are located between the intake manifold and cylinder heads, providing two air passages for each cylinder.
One air passage is always open and the other passage switches from closed to open by means of a valve plate.
Below 3000 rpm , this valve plate is closed to improve low-speed and cold engine performance.
Above 3000 rpm , this valve plate opens to improve high-speed engine performance.
The valve plates are opened and closed by the IMRC deactivation motor, which is controlled by the powertrain control module (PCM)
There is a TSB addressing this DTC and it may or may not be due to a PCM programming error. You should take it to a Ford dealer and let them inspect the system and reprogram the PCM. The TSB is number 02-15-3 dated 08/05/02.

Article No.: 02-15-3
Date: 08/05/02
DRIVEABILITY:
Malfunction indicator lamp (mil) illuminated with diagnostic trouble code (DTC) p1518 intake manifold runner control (IMRC) - vehicles equipped with 3.0 liter 4v engine only.

FORD:
1996 - 1999 Taurus

MERCURY: 1996 - 1999 Sable
ISSUE:
Some vehicles equipped with the 3.0LE 4V Duratec engine may exhibit a Malfunction Indicator Lamp (MIL) illuminated with a Diagnostic Trouble Code (DTC) P1518, Intake Manifold Runner Control (IMRC) stuck open, with no driveability concerns present. This may be caused by the calibration of the Powertrain Control Module (PCM).

If the SES light is out, it means that the condition that turned it on no longer exists but the code will still be stored in the PCM's memory.

Technical Service Bulletin: #8583

I will have to retest and run the rpms above 3K and see if it comes back on, but it sounds like it may just be a reprogram at Ford dealer.
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Saturday, December 1st, 2007 AT 12:13 PM

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