P05F3

Symptoms

• Check Engine Light and Emissions Control Warning Light Illuminates
• Complete failure of the SCR or DPF system
• No activation of the system when the ignition is turned on
• Increased emissions
• Possible power limitation after some time

Causes

• Open relay coil control circuit
• Blown relay control circuit fuse
• Relay control connector oxidation
• ECU malfunction (does not generate a control signal)
• Mechanical damage to the relay (broken control winding)

How to Fix

1. Read all codes, check for associated SCR/DPF/AdBlue codes
2. Locate the aftertreatment power relay in the fuse box
3. Check relay control circuit fuse
4. Measure the resistance of the relay control winding (normal: 70–120 Ohm, open circuit - infinity)
5. Check the presence of a control signal from the ECU to the relay (relay activation by scanner)
6. Replace the relay or repair an open circuit in the control circuit

Related codes

Error P05F3 by Vehicle Brand