Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide - Manual (Page 18)

15
Diagnostics
Service Codes Summary (continued)
5 Flashing LIGHTs or
DDM – Dashes "--" 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
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 31 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)
3) Faulty PCU (leaks air during supply tank check)
5 Flashing LIGHTs and
CHECK TIRES Solid Code No. Causes (numbered in order of likely occurrence)
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)