Cummins ISB CM850 (2003-06) Fault Code: 1699 PID: SPN: 1761 FMI: 2 Catalyst Tank Level Sensor – Data Erratic, Intermittent, or Incorrect. Catalyst solution level is not changing with engine operating conditions.

This fault code is triggered when the catalyst solution level reading in the catalyst tank does not change with engine operating conditions. If the catalyst dosing control unit indicates that catalyst injection has occurred, but the catalyst tank level has not changed, this fault code will be triggered. This fault will also be triggered if catalyst injection has not occurred, but a drop in the level of the catalyst solution has been detected.

Use INSITE? electronic service tool to make sure the adjustable parameter Linear Urea Tank Volume is adjusted correctly. This fault code can trigger if this parameter is not adjusted for the correct urea tank volume.

Possible causes:

1)Malfunctioning catalyst tank level sensor
2)Plugged or restricted catalyst solution lines
3)Plugged or restricted aftertreatment nozzle
4)External leaks in the catalyst tank or catalyst solution lines
5)Catalyst tank level sensor tampering.

On-Board Diagnostics (OBD) Information:

1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails
2)The ECM turns off the malfunction indicator lamp (MIL) when the diagnostic runs and passes. The diagnostic requires a quantity of diesel exhaust fluid (DEF) to be dosed. Depending on the application and system configuration, this may be up to 3 liters (3.17 qt). The MIL and fault code can also be cleared using INSITE? electronic service tool.
3)The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

Possible repairs:

1)Repair or replace the catalyst solution lines.
2)Clean or replace the aftertreatment nozzle.
3)Remove any external tampering devices. Install the correct catalyst solution tank.