What does P1530 mean on a Chevy?

P1530. Ignition Timing Adjustment Switch Circuit. Applies to Silverado, Sierra, Tahoe, Yukon, Suburban.

What causes P1530 on a Chevy?

Timing test switch left grounded after a timing-check procedure Short to ground in the ignition timing adjustment switch circuit Corroded timing connector near the distributor or PCM breakout Aftermarket chip or timing module tapped into the test switch circuit

How do I fix P1530 on a Chevy?

Verify the timing test switch is open and not left in test mode Inspect the timing connector for corrosion or a forgotten jumper Test the switch circuit for a short to ground with a multimeter Remove any aftermarket timing devices spliced into the circuit Clear and road test above 1 MPH to confirm the switch reads off in closed loop

Code

P1530

Ignition Timing Adjustment Switch Circuit

Category: Powertrain - Ignition
Severity: Check Engine Light
Applies to: Silverado, Sierra, Tahoe, Yukon, Suburban
Related: No single generic twin. See OBD Codes List

What it means

P1530. Ignition Timing Adjustment Switch Circuit. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Yukon, Suburban.

Findings, check these first

Timing test switch left grounded after a timing-check procedure
Short to ground in the ignition timing adjustment switch circuit
Corroded timing connector near the distributor or PCM breakout
Aftermarket chip or timing module tapped into the test switch circuit

Standard procedure

Verify the timing test switch is open and not left in test mode
Inspect the timing connector for corrosion or a forgotten jumper
Test the switch circuit for a short to ground with a multimeter
Remove any aftermarket timing devices spliced into the circuit
Clear and road test above 1 MPH to confirm the switch reads off in closed loop

Look up another code

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Sources and review

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Last updated 2026-09-19.

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