CTIS question

[tmaxxgod4]

when my truck runs all the lights on the CTIS flash. can anyone tell me whats wrong?

 

[wheelspinner]

It's not working correctly.

 

[TexAndy]

From the CTIS troubleshooting guide, pgs 13-14:

5 Flashing LIGHTs Code No. Causes (numbered in order of likely occurrence)
Low Pressure 26, 27 CHANNEL PRESSURE LOSS (Channel only checks pressures): Pressure check of
given channel returns low reading (< 5 psig) indicating an extreme loss of pressure.
Repair and request pressure check to clear (press any mode button or run flat).
1) Open or broken line between PCU and wheel valve
2) Significant hub air seal leakage
3) Kinked or plugged line between supply tank and PCU
4) Faulty PCU sensor (ex. frozen water contamination)
5) PCU failure (supply off or control off)
6) Pressure switch failure (shorted closed)
Low Air Supply 32 PRESSURE SWITCH REMAINS OPEN (System non-operative until switch closes):
For 4 minutes at vehicle speed > 20 mph pressure switch failed to close.
Repair and allow pressure switch to close to clear.
1) Compressor governor cutout set too low
2) Pressure switch unplugged, or open wire
3) Faulty pressure switch (failed open)
4) Faulty compressor
5) Broken, kinked, or plugged line from compressor to supply tank
Atmospheric 35 OUT OF RANGE ATMOSPHERIC READING (System waits to check pressures):
Atmospheric pressure check indicates vented PCU pressure is outside of valid
atmospheric range (5-20 psia).
Repair and request pressure check to clear (press any mode button or run flat).
1) Poor ground connection to PCU sensor
2) Faulty PCU sensor (ex, frozen water contamination)
3) Faulty PCU or blocked PCU exhaust vent
Inflate Trend 36, 37 INFLATE PRESSURE LOSS (System disables given channel): Given channel loses > 6
psi while inflating.
Repair and cycle ignition to clear.
1) Damaged tire or tire leakage
2) Leaking lines or seals
3) Faulty PCU (control solenoid off or additional channel stuck on)
Deflate Trend 14 FAILURE TO DEFLATE PROPERLY (System disables deflates): System gains >10 psi
pressure while attempting to deflate, or does not lower tires by even a small amount
of the intended change.
Repair and cycle ignition to clear.
1) Plugged or restricted PCU vent line
2) Faulty PCU relief valve
3) Poor ground connection to PCU sensor
4) Contaminated PCU
5) Faulty PCU
13Diagnostics
Service Codes Summary (cont’d.)
5 Flashing LIGHTs Code No. Causes (numbered in order of likely occurrence)
PCU Sensor 33, 34 NO PCU SENSOR READING (System non-operative): No sensor voltage to ECU.
Clears 5 seconds following a valid reading.
1) Sensor is electrically disconnected
2) Pressure signal wire (XDCR SIGNAL) is shorted to ground, or open
3) PCU sensor VREF wire is shorted to ground, or open
4) Faulty sensor
Pressure Switch
31
PCU SENSOR READING TOO HIGH (System non-operative): Sensor voltage higher
than allowed.
Clears 5 seconds following a valid reading.
1) Pressure signal wire (XDCR SIGNAL) is shorted to power or XDCR VREF
2) Faulty sensor
PRESSURE SWITCH SHORTED or FAILED CLOSED (System waits to check pres-
sures): Pressure switch is read as closed, but pressure check of supply tank
indicates insufficient air pressure to continue.
Repair and request pressure check to clear (press any mode button or RUN FLAT).
1) Wire to pressure switch shorted to ground
2) Faulty pressure switch (failed closed)


Sorry for the lack of formatting. You can read it more legibly in the actual PDF

 

[doghead]

So, do you think the TM would be helpful?

 

[TexAndy]

Other than the lights flashing on the control panel, what's wrong with the CTIS on your truck?

 

[hklvette]

Time to dig into it. 5 lights is typically any "catastrophic" failure of the CTIS system. Try this:

Initial Conditions:
-both battery and ignition switches off.
-CTIS controller plugged in
-air tanks (at least the wet tank) drained

1) Start truck, build air until CTIS cut-in pressure (~120psi) is reached
*during this step, the HWY light should be blinking
2) Once cut-in pressure is reached, CTIS unit will pressurize the lines going to the wheel valves, but not open the wheel valves themselves (supposedly) to check for leaks
*watch the air pressure gauges during this step. If there is a sudden drop in pressure in either of them and the 5 lights start to flash, there is a large air leak somewhere.
3) If you get 5 lights BEFORE the pneumatic controller on the floor "clicks", odds are there's an electrical problem in the system.

That ought to be enough to get you started.

 

[1 Patriot-of-many]

5 lights can be anything from major leak, to having a schrader valve where the airline on the wheel attaches to the turret(a good indicator of this is to try airing up each tire manually at the wheel valve stem If you can't air the tire up there is a schrader valve where the line connects to the wheel turret at the rim, use a scrader valve removal tool) to having a flat tire(you need about 10psi in every tire for the CTIS to function. Try holding down the run flat button at the bottom for a couple seconds, see if it starts sending air to the tires. I have a couple trucks I need to start the CTIS in run flat mode, after a few minutes I can turn it off. Good luck. I had no lights on my 936A2, that was a bad pneumatic controller.

 

[MO MV man]

My five flashing lights were cured by listening closely for air leaks, tightening a few fittings that had tiny leaks and finally the little brass pressure relief valve-that ended up being the culprit after all.
It just wouldn't hold 120PSI consistently enough.
Cheap and easy fix.
Hope yours is that easy.

It's been working great ever since.