My 94 D1 is telling me fault code 48... Stepper Motor

Several OBD1 Engine Fault Codes pages (and on a previous post here) list various continuity tests to perform prior to just replacing a part.
For example my Code 48 says:

"Stepper Motor. Refer to tests 15 and 16 of continuity test procedure.
Check road speed sensor- refer to test 25 of continuity test procedure.”

Where are these continuity test procedures located? I have searched the RAVE CD to no avail.

BTW... the engine has 102K, starts like a champ, runs ultra smooth. I did notice that the RPMs sometimes fluctuate by a 100 to 200 RPM's every so often when I was setting the timing after putting in new plugs. But not a constant fluctuation.



Joe

 

continuity tests usually refer to a test for conduction, like on a motor you may test the resistance across the coils, or on a speed sensor (if you are talking about the wheel sensors on the ABS system) then they should produce a level of resistance that will fluctuate as the wheel turns. However I would suspect that you would need a base reading to compare it to (kind of like measuring a speaker usually 4 or 8 ohms). but I may be misunderstanding what you mean all together.

if you have the base reading and it is in Ohms then a digital multimeter (DMM) or an ohm meter should give you some results.

 

pull the stepper motor out and clean it really well

 

Thanks Chris...

I know what a continuity test is... it sounds like in some Rover publication somewhere there is defined a specific Continuity Test Number 15, and a specific test number 12, and so on

What publication is that?

Joe

 

those tests are to check the wiring to the motor, or sensor, or whatever fault you have... electrical faults are either componant, wiring to compnant, or componant control. they have you check the wiring before the part is condemnd

 

where did you get this info?

"Stepper Motor. Refer to tests 15 and 16 of continuity test procedure.
Check road speed sensor- refer to test 25 of continuity test procedure.”

according to my info 48 is Idle Air Control Valve and my alldata (its for 95 but shows the same info I found online from a tech site) explains how to test the ECM plug with a DMM for faults.

according to my tech sheet for code 48 you will need to unplug the ECM and test between pins 1 and 26 (with ignition off) and you will be looking for a reading of 40 to 60 ohms if you do not get this reading then you have a fault on the RG wire (pin 1), the GW wire (pin 26), or the idle air control valve. if you have a good reading then you need to test between pins 28 and 29 (with ignition off) and you will be looking for a reading of 40 to 60 ohms if you do not get this reading then you have a fault on the O wire (pin 29), the UB wire? (pin 28), or the idle air control valve. if you still have a good reading you have to test between pin 20 and ground with the ECM plugged in and the ignition on (not sure if the engine should be running or not, I would imagine off) with the throttle closed you should be reading between .085V and .545V and with the throttle fully open you should read 4.2V to 4.9V if you do not get these readings then you have a fault on the R wire (pin 20), the RB wire(does not say location),the Y wire(does not say location), or the throttle position sensor.

If this does not help don't know what else to try.

 

THANK YOU... THANK YOU... THANK YOU... I will give this a shot... a new Idle Air Control Valve (aka Stepper Motor) can be had for about $50... probably $10 form a parts yard. but I love testing and tinkering and making 100% sure that a part should replaced before I do so.

How has your experience been with ALLDATA... worth the $?

Joe

 

I actually got the disk free from a friend who had a small garage that went under. It is only good for land rovers 95 and up but so far I like it, mostly the same as the rave CD however it gives average repair times (for quotes) as well as prices of parts (however the prices aren't always accurate but the part numbers are) It is also quite a bit easier to navigate through alldata than it is to navigate through the rave cd.