ECM Controllers & Monitors

521-0791 Electronic Control Group for Cat 320 323 330 336 C9.3 C7.1

Q: What numbers are documented for 521-0791?

Primary Cat Part Number: 521-0791. Same-number Formatting Variant: 5210791. Manufacturer-listed Reman Alternative: 11R-1254. Relationship labels distinguish formatting aliases, direct interchanges, remanufactured references and related assemblies.

Q: How do I confirm 521-0791 before ordering?

Match the complete part number, compare the connector or mounting arrangement with the product photos, and confirm the machine or engine model and serial range. Send clear photos of the original unit when requesting a quote.

521-0791 Electronic Control Group for Cat 320 323 330 336 C9.3 C7.1, OEM/reference 521-0791, Electronic Control Group / ECM, product view 1

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OEM / reference521-0791

SpecificationElectronic Control Group / ECM

Catalog ID53589501

Unprogrammed air-cooled electronic control group identified by official Cat part number 521-0791. The manufacturer compatible-model record includes 320, 323, 330, 336 and other excavators plus C9.3 and C7.1 engines. Cat lists 11R-1254 as the remanufactured ECM alternative. Two selected owned photographs show the same module, including a readable 521-0791 manufacturer label.

Product Type: Electronic Control Group / ECM
Programming State: Unprogrammed
Cooling: Air cooled
Compliance: RoHS compliant
Condition: New replacement component

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Part-number relationships

Relationship	Reference family	Number
Primary Cat Part Number	Official electronic-control-group identity	521-0791
Same-number Formatting Variant	Search alias only	5210791
Manufacturer-listed Reman Alternative	Cat Reman ECM New With Core (A6E2 air cooled, programmable)	11R-1254

Product fitment guide

Part numbers and compatible models

Quickly compare the reference number and recorded machine applications. Use the original photos and the checklist before ordering.

Part identification

Reference numbers

Primary number

521-0791

Manufacturer number

11R-1254

Formatting alias

5210791

Formatting aliases are the same number written differently. Related assemblies and remanufactured numbers are not presented as direct interchanges.

Product summary

Electronic Control Group / ECM

Category: ECM Controllers & Monitors
Catalog ID: 53589501
Photo views: 2

Before ordering

Confirm these details

Match the complete part number on the original component label.
Compare the front layout and visible configuration with the product photos.
Compare connector count, connector shape and keying before installation.
Confirm the exact machine model and serial range before ordering.

Machine fitment

Compatible model references

5 model references

Official Cat Excavators: 317 / 320 / 320 GC / 323 / 323 GC / 323 GX / 325 / 326 / 326 GC / 330 / 330 GC / 333 / 335 / 336 / 336 GC / 340 / 345 GC / 349 GC / 350
Official Cat Wheeled Excavators: M314 / M315 / M315GC / M316 / M317 / M318 / M319 / M320 / M320GC / M322 / M323 / M323F
Official Cat Engines: C9.3 / C7.1 / C9.3B / C4.4
Additional official equipment: D4 / D5 / D6 / D6T / D6 XE / D6XE / D7 / 953 / 963 / 973 / RM400
Fitment limitation: Confirm 521-0791, software/calibration, connector keying, machine serial and configuration before shipment

Compatibility lists identify searchable model families, not every production serial range. Confirm the original part number and machine serial number before purchase.

Quick fitment answers

Common questions about 521-0791

Which machines use 521-0791?

Recorded compatible model references include Official Cat Excavators: 317 / 320 / 320 GC / 323 / 323 GC / 323 GX / 325 / 326 / 326 GC / 330 / 330 GC / 333 / 335 / 336 / 336 GC / 340 / 345 GC / 349 GC / 350, Official Cat Wheeled Excavators: M314 / M315 / M315GC / M316 / M317 / M318 / M319 / M320 / M320GC / M322 / M323 / M323F, Official Cat Engines: C9.3 / C7.1 / C9.3B / C4.4, Additional official equipment: D4 / D5 / D6 / D6T / D6 XE / D6XE / D7 / 953 / 963 / 973 / RM400, Fitment limitation: Confirm 521-0791, software/calibration, connector keying, machine serial and configuration before shipment. Confirm the complete part number and machine serial range before ordering.

What numbers are documented for 521-0791?

Manufacturer number: 11R-1254. Formatting aliases for the same number: 5210791.

How do I confirm 521-0791 before ordering?

Match the complete part number on the original component label. Compare the front layout and visible configuration with the product photos. Compare connector count, connector shape and keying before installation. Send clear photos of the original unit and connector layout when requesting a quote.

Continue comparing verified references from the same system.

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