Code P0502

retroedaddy

retroedaddy

Infidel
Joined
Apr 7, 2010
Location
Bahama NC
Anyone have a abs scan tool?I am getting a P0502 code on the wife's SUV,it reads as speed sensor A.It is a 2002 Olds Bravada with the smart trac auto 4X4.I also have a dead speedo,motor in Limp mode and my ABS light as well as my Brake light are on.The display says service brake system.So any ideas on what Speed Sensor "A" is?It looks like there are 6 speed sensors on the truck and I don't want to start randomly replacing them.Also the auto store says I need the abs scan tool to access why the ABS light is on too.It all started at once,could all the problems be one sensor?I look forward to the wealth of info I know I am sure to get on here!!:popcorn:
 
i do know that all the lights came on and you lost your speedometer due to the sensor being bad. I am a tech but am currently out of work due to back surgery. I will call the shop tommorow and findout for sure which one it is but usually when you loose your speedometer it is the one in your t-case that goes bad! The ones at the wheels usually dont cause you to loose your speed readings but will cause your ABS to act funny and "pulsate" when there not suppost to.
 
PM me your number and I'll look it up first thing tomorrow.
 
4wheelBUM said:
i do know that all the lights came on and you lost your speedometer due to the sensor being bad. I am a tech but am currently out of work due to back surgery. I will call the shop tommorow and findout for sure which one it is but usually when you loose your speedometer it is the one in your t-case that goes bad! The ones at the wheels usually dont cause you to loose your speed readings but will cause your ABS to act funny and "pulsate" when there not suppost to.
Click to expand...
Man thank you.That's helpful.
 
yeah a bad VSS will cause an ABS light...learned that one the hard way.
Vehicle in limp mode because it doesn't know how "fast you are going" sso it doesn't know which gear to go in...
speedo dead because again outpuit speed sensor not sending signal

Id bet dollars to donuts the tcase out sensor is bad, coated, or unplgged
 
SkyHiK5 said:
yeah a bad VSS will cause an ABS light...learned that one the hard way.
Vehicle in limp mode because it doesn't know how "fast you are going" sso it doesn't know which gear to go in...
speedo dead because again outpuit speed sensor not sending signal

Id bet dollars to donuts the tcase out sensor is bad, coated, or unplgged
Click to expand...
Cool thanks,pulled it today,Looks OK but then again I don't have X-ray Vision.
 
Alright I pulled and replaced both Speed Sensors in the Transfer case.Had the battery disconnected then entire time.Got it back together and there is no change at all.Any ideas?
 
Word for word from alldata
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Test 6-15

Circuit Description
The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM) . The VSS assembly is a permanent magnet generator. The VSS produces an AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the pulsing voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and Torque Converter Clutch (TCC) scheduling.
When the PCM detects a low vehicle speed when there is a high engine speed in a drive gear range, then DTC P0502 sets. DTC P0502 is a type B DTC.

Conditions for Running the DTC
No MAP sensor DTCs P0105, P0107 or P0108.
No TP sensor DTCs P1120 or P1220.
No TFP manual valve position switch DTC P1810.
The engine vacuum is 0 - 105 kPa (0 - 15 psi) .
The TP angle is 20 to 50 percent.
The engine speed is 3,200 to 4,775 RPM.
The transmission is not in PARK or NEUTRAL.
Conditions for Setting the DTC
The transmission output speed is less than 150 RPM for 3 seconds.

Action Taken When the DTC Sets
The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
The PCM commands second gear only.
The PCM commands maximum line pressure.
The PCM inhibits TCC engagement.
The PCM freezes shift adapts from being updated.
The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
The PCM stores DTC P0502 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
A scan tool can clear the MIL/DTC.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step tests the VSS assembly circuit.
This step tests the integrity of the VSS Assembly.

hope this helps.
 
Wow man that is a lot of info.I appreciate that.I will look that over tomorrow after a few less :beer::beer::beer:
 
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