Chevy Codes List

Chevy-enhanced trouble code lookup
for Chevrolet, GMC, Buick and Cadillac.

Repair Order

282 Chevy-enhanced codes on file

Code
P1221

Fuel pump secondary circuit low

Category
Powertrain - Fuel/Air Metering
Severity
Check Engine Light
Applies to
Silverado, Sierra, Tahoe, Suburban with 4.8L, 5.3L, 6.0L V8 2003 to 2007.
Related
No single generic twin. See OBD Codes List

What it means

P1221. Fuel pump secondary circuit low. The fuel pump control circuit has low voltage. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Suburban with 4.8L, 5.3L, 6.0L V8 2003 to 2007..

Findings, check these first

  • Failing fuel pump drawing high current
  • Blown fuel pump fuse in the secondary circuit
  • Open or chafed fuel pump power wire
  • Corroded fuel pump ground connection
  • Faulty powertrain control module fuel pump driver

Standard procedure

  1. Check the fuel pump fuse and relay
  2. Measure fuel pump voltage at the pump under load
  3. Inspect the fuel pump harness and ground for damage
  4. Test fuel pump current draw and fuel pressure
  5. Replace the fuel pump only after the circuit tests pass

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Sources and review

Review: qualified. Read the source limits below.

  • OBDII Code P1221 CHEVROLET - Fuel Pump Secondary Circuit Low | Engine-Codes.com

    archived reference page (engine-codes.com via Wayback Machine)

    Supports: code identity and Chevrolet application, with a fuel pump meaning

    Fetched directly. The Chevrolet page titles P1221 as fuel pump secondary circuit low, not a throttle position correlation.

  • OBDII Code P1221 GMC - Fuel Pump Secondary Circuit Low | Engine-Codes.com

    archived reference page (engine-codes.com via Wayback Machine)

    Supports: code identity and GM application, with a fuel pump meaning

    Fetched directly. The GMC page repeats the fuel pump secondary circuit low meaning for the same code.

  • P1221 on obdii.pro (third-source cross-check)

    live reference page (obdii.pro)

    Supports: shows the meaning is not consistent across GM sources

    Cross-check 09/26: obdii.pro carries no GM-keyed definition for P1221 and its Oldsmobile entry says traction control system malfunction. Two engine references and this source disagree, so the code is platform dependent.

Source caveat: description and cause/action lists changed from throttle position sensor 1-2 correlation to fuel pump secondary circuit low. Cross-check note: GM meanings for this number are platform dependent, so the page keeps the two-source fuel pump wording and this record carries the conflict.

Last updated 2026-09-25.

Report a correction for P1221. Include your vehicle, the issue and a source if you have one.

This fault is part of the Chevy P1xxx fuel and ignition codes guide. It covers the family and the order to check it.

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