4x4 light blinking P0837, P0838 Manual Shift Transfer Case
03-24-2019, 10:47 PM
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4x4 light blinking P0837, P0838 Manual Shift Transfer Case
I searched the forum but didn’t find much. 2003 CTD CC with manual shift transfer case. Son was driving today in 2hi on highway and 4x4 light started flashing. He pulled over to see what was up and tried to put the truck in 4hi then 4lo and it wouldn’t engage either, the shifter moves into position but no 4X4. It drives fine in 2hi. But the light keeps flashing.
Ran diagnostic on Smarty and it gives P0837 “4wd switch performance” and P0838 “switch circuit low”.
The truck is manual shift transfer case. What switch is it talking about? The manual shift TC’s don’t have a motor on them like the shift on fly electric TC selector trucks, right?
Where can I find this “switch” and what does it do?
Any help would be appreciated.
Thanks,
TXPower
Ran diagnostic on Smarty and it gives P0837 “4wd switch performance” and P0838 “switch circuit low”.
The truck is manual shift transfer case. What switch is it talking about? The manual shift TC’s don’t have a motor on them like the shift on fly electric TC selector trucks, right?
Where can I find this “switch” and what does it do?
Any help would be appreciated.
Thanks,
TXPower
03-25-2019, 09:43 AM
#2
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Do you have a service manual? If not, you should be able to find one online for free. Below is copied from the service manual, pg.21-618. I'm not sure if this is your problem, but its a good place to start. Check out the attachment for more info.
TRANSFER CASE POSITION SENSOR
The transfer case position sensor is an electronic
device whose output can be interpreted to indicate
the transfer case’s current operating mode. The sensor
consists of a five position, resistive multiplexed
circuit which returns a specific resistance value to
the Powertrain Control Module (PCM) for each transfer
case operating mode. The sensor is located on the
top of the transfer case, just left of the transfer case
centerline and rides against the sector plate roostercomb.
The PCM supplies 5VDC (+/- 0.5V) to the sensor
and monitors the return voltage to determine the
sector plate, and therefore the transfer case, position.
TRANSFER CASE POSITION SENSOR
The transfer case position sensor is an electronic
device whose output can be interpreted to indicate
the transfer case’s current operating mode. The sensor
consists of a five position, resistive multiplexed
circuit which returns a specific resistance value to
the Powertrain Control Module (PCM) for each transfer
case operating mode. The sensor is located on the
top of the transfer case, just left of the transfer case
centerline and rides against the sector plate roostercomb.
The PCM supplies 5VDC (+/- 0.5V) to the sensor
and monitors the return voltage to determine the
sector plate, and therefore the transfer case, position.
03-25-2019, 09:58 AM
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Mike67RS, thanks for the reply. That definitely explains why the error code talks about voltages and answers my question about a “switch”.
Thanks,
TXPower
Thanks,
TXPower
I searched the forum but didn’t find much. 2003 CTD CC with manual shift transfer case. Son was driving today in 2hi on highway and 4x4 light started flashing. He pulled over to see what was up and tried to put the truck in 4hi then 4lo and it wouldn’t engage either, the shifter moves into position but no 4X4. It drives fine in 2hi. But the light keeps flashing.
Ran diagnostic on Smarty and it gives P0837 “4wd switch performance” and P0838 “switch circuit low”.
The truck is manual shift transfer case. What switch is it talking about? The manual shift TC’s don’t have a motor on them like the shift on fly electric TC selector trucks, right?
Where can I find this “switch” and what does it do?
Any help would be appreciated.
Thanks,
TXPower
Ran diagnostic on Smarty and it gives P0837 “4wd switch performance” and P0838 “switch circuit low”.
The truck is manual shift transfer case. What switch is it talking about? The manual shift TC’s don’t have a motor on them like the shift on fly electric TC selector trucks, right?
Where can I find this “switch” and what does it do?
Any help would be appreciated.
Thanks,
TXPower
03-25-2019, 10:13 AM
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How to ohm test it?
I have a multimeter that measures ohms but have never performard an ohms test. Can someone give me a tutorial on how to set the multimeter and then how to perform the test once I get the transfer case position sensor out of the transfer case?
Thanks,
TXPower
Thanks,
TXPower
03-25-2019, 10:23 AM
#5
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...Ben
03-25-2019, 11:11 AM
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Man an I hate to seem dumb but I am electronically. So I set the dial indicator of my battery powered multimeter to ohms? Assuming the plug end of the sensor has 2 prongs, do I just put one probe each from
the multi meter on to each prong of the sensor and then depress the plunger on the sensor to check the ohms?
thanks,
TXPower
the multi meter on to each prong of the sensor and then depress the plunger on the sensor to check the ohms?
thanks,
TXPower
Just make sure that the device upon which you want to test resistance is unpowered (in other words unplugged)...If you know what the expected reading will be, set your ohmmeter to that range...Put the ohmmeter probes across the circuit you want tested on the device, and read the meter......Ben
...Ben
...Ben
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