Mercedes Fuel Pump Relay KPR 0035451205 KR0003 Relay KE-Jetronic Tested
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Genuine fuel pump relay (KPR) 003 545 12 05 / KR0003 for Mercedes vehicles with KE-Jetronic.
Genuine spare part · Personally function-tested · Control electronics instead of a simple switching relay
✓ Function tested
Condition of this part
Used genuine part, personally tested and functional. The housing shows light scratches on the ribbed top and a small paint mark on one edge; the plug contacts are slightly tarnished from age. All pins are present and straight, with no breaks or cracks.
Function and location
The KPR is not a simple switching relay but a small piece of control electronics: it pre-runs the fuel pump for about 2 seconds when the ignition is switched on, keeps it active during cranking and while the engine is running, and switches it off as a safety measure when the engine is stopped. Depending on the version, this series also controls the cold start valve and the oxygen sensor heater and handles rev limiting.
The relay is installed in the control unit/electronics box in the engine bay (plenum chamber), next to the injection control units.
How can you tell if a fuel pump relay is faulty?
- Engine doesn't start because the fuel pump doesn't run
- Engine stalls sporadically
- Misfires while driving
Compatible vehicles
According to repair documentation, assigned to the W124 family from the KE-Jetronic era (manual transmission version, 1980s model series). The number is no longer listed in current catalogs – so before buying, please be sure to compare the part number on your old part; the relay is only guaranteed to fit if the number is identical.
Part numbers: Mercedes-Benz 003 545 12 05 (also written as 0035451205), listed internally as KPR (fuel pump relay) KR0003. Not to be confused with 003 545 13 05, 003 545 19 05, 003 545 20 05, 002 545 21 05 (M102 group) or 003 545 24 05, 002 545 92 05 (M103 group) – these do NOT fit this item.
⚠ Important: compare the part number before buying
The number 003 545 12 05 is decisive for compatibility and is no longer listed in current catalogs. Repair documentation assigns it to the W124 family from the KE-Jetronic era (manual transmission version, 1980s model series). Before buying, please be sure to compare the part number on your old part.
Does not fit:
- KPR 003 545 13 05, 003 545 19 05, 003 545 20 05, 002 545 21 05 (M102 group)
- KPR 003 545 24 05, 002 545 92 05 (M103 group)
- As a general rule: Mercedes fitted different KPR versions for each engine/transmission combination – always check against the part number
Does this part fit your car? Send us the VIN (chassis number) and model year – we'll check it for free: 0179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.
FAQ
Is the relay tested?
Yes, it has been personally function-tested and works flawlessly. The housing shows only light signs of use, such as scratches on the ribbed top and a small paint mark on one edge.
Is the relay guaranteed to fit my vehicle?
Only if the part number 003 545 12 05 matches your old part exactly. Mercedes fitted different KPRs depending on the engine/transmission version, and this number can no longer be checked against current catalogs.
How can I tell a KPR is defective?
Typical signs are an engine that doesn't start because the fuel pump doesn't run, as well as sporadic stalling or misfires while driving.
Related categories: Relays
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