Variant 1
Applies to: AMS1
What does Scania AMS fault code 4354 mean?
The reductant pump needs to be faster than expected in order to maintain the correct reductant pressure.
What causes Scania DTC 4354?
- The fault occurs if reductant cannot reach the reductant doser on the silencer/V117. - The reductant is frozen because the reductant heating is not working. - Fault in the pressure sensor for the reductant doser on the silencer/V117 - Dirt in the system that clogs the filter or damages components. - Fault on the reductant pump: - Check valves do not open and close as they should. - The overflow valve in the reductant pump opens when the pressure is too low. - Filter blockage in the system: - Rductant pump prefilter or main filter. - T116 Reductant pick-up unit prefilter. - V231 Reductant doser prefilter (downstream of turbocharger). - V117 Reductant doser prefilter (on the silencer). - Leakage or blockage in: - T116 Reductant pick-up unit suction pipe. - Hose between the reductant pick-up unit and reductant pump. - Hose between the reductant pump and V231 reductant doser (downstream of turbocharger). - Hose between the V231 reductant doser (downstream of turbocharger) and the V117 reductant doser (on the silencer).
How to fix Scania AMS fault code 4354?
- Run the Wizard on dirt in the SCR system.
- Check whether fault code EEC 4358 is active.
- If the fault code is active:
- Renew the prefilter in V231 reductant doser (downstream of turbocharger).
- Renew the prefilter in V117 reductant doser (on the silencer) and the main filter in the reductant pump.
- To verify that the fault has been rectified, run Exhaust gas aftertreatment, troubleshooting the liquid components of the SCR system > Metering test > Low dosage level.
- Check whether the reductant temperature was below 0°C when the fault code was activated.
- Check the current reductant temperature under T116, Reductant pick-up unit.
- Run Exhaust gas aftertreatment, troubleshooting the liquid components of the SCR system to find any blockages in the reductant circuit or faults in the pressure sensor of the reductant doser.
- Note: If the fault code cannot be recreated, run Exhaust gas aftertreatment, troubleshooting the liquid components of the SCR system > Metering test > High dosage level.
Variant 2: Reduction pump, increased speed to reach pressure
Applies to: AMS2
Detection
The reductant pump needs to run faster than expected to maintain the correct reductant pressure.
Possible cause
- Blockage in reductant circuit’s pressure side: - The pump's main filter. - Doser prefilter. - Doser internal port. - External force that squeezes any of the hoses between the pump and the dosers. - Blockage on the reductant circuit's suction side: - Frozen reductant. - Prefilter, reductant pick-up unit T116. - Prefilter, reductant pump V183. - Hose between reductant pick-up unit and pump. - Leakage upstream or downstream of the pump: - Low reductant level, pump sucking in air. - Hoses between reductant pick-up unit, pump and reductant doser. - Internal leakage in reductant pump V183. - Electrical fault: - Pressure sensor in reductant doser V117. - Cable harness between pump, reductant doser and EEC.
How to fix
- Check the reductant level and whether the reductant has frozen.
- If the reductant has been frozen, check that the reduction hoses are taped together with the coolant hoses.
- A maximum of 1 cm may be exposed.
- Inspect hoses in and out of the pump for external signs of leakage.
- Replace leaking components.
- If no leakage is found, run Troubleshooting of the SCR system fluid part to determine the part of the circuit in which the problem is located.
- Check the cable harness between the reductant pump, reductant doser and EEC control unit.
- Check the reductant pressure.
- If the reduction pressure does not change at all, replace the reductant doser.
- If the reductant pressure varies, replace the reductant pump.
- For troubleshooting purposes, consider temporarily switching to components you know are working before performing any permanent actions.
- Verification Leave the vehicle idling for 2 minutes before deactivating the fault code.
This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.