Original GoTech guide. Check the exact vehicle and current service information before using procedures or specifications.

When to investigate a slipped crankshaft reluctor ring

Looking for general timing-chain symptoms, affected-year context or replacement intervals? Start with the GM 3.6L timing-chain problems guide. This page covers the separate crankshaft-reference concern described by PIP3423P.

Codes only?Work through related faults and timing checks first.

Cause still unexplained?Check the bulletin’s application and prerequisites.

Movement established?Follow the applicable repair procedure; don’t substitute a timing kit.

Why this is different from chain wear

The chains control the mechanical relationship. The reluctor supplies a crankshaft-position reference. If that reference moves, the reported cam/crank relationship can be wrong even when replacing a chain would not address the cause.

P0008/P0009 and P0016–P0019: use the bulletin’s conditions

PIP3423P does not say to replace a crankshaft whenever a correlation code appears. It places this check after service-information diagnosis and chain/tensioner checks have not found the cause.

Read PIP3423P in the right order

  1. Match the listed vehicle and engine application. The concern is two or more of P0016, P0017, P0018, P0019, P0008 or P0009.
  2. Check chains and tensioners and follow service-information diagnosis.
  3. If the cause remains unresolved, consider whether the crankshaft reluctor has moved.

The August 9, 2018 revision specifies crankshaft replacement if movement is confirmed. If movement is uncertain, it calls for comparison with a new crank before disassembly.

Read GM PIP3423P, including its application list and photographs (PDF) →

Historical bulletin, superseding PIP3423N. Check current application-specific service information before selecting a repair.

Use the GM 3.6L diagnostic worksheet to record the related faults, chain and tensioner checks, test conditions and unresolved findings before moving to the reluctor inspection.

What the reference photographs can show

comparison of bad vs good reluctor wheelEnlarge the reluctor comparison

Compare the reference features shown in the original photographs. Use the bulletin and the exact application’s inspection method to establish movement; the code pattern cannot do that for you.

Keep overall engine condition as a separate decision

The original engine photographs give context. They do not decide whether your engine needs a crankshaft, further repair or replacement.

close up of bad reluctor wheelEnlarge the engine photograph

Don’t skip the finding

If movement has not been established, return to the diagnostic evidence. If it has, use the applicable service procedure to plan the repair. Neither a new timing kit nor a reluctor repair should be selected simply because the code list looks familiar.

If you still need to compare cam/crank signals, review the annotated waveform references and their source conditions. A waveform discrepancy alone does not establish that the reluctor has moved; use the applicable inspection method to confirm that finding.

Still investigating? Return to the diagnostic decisions →Check whether your waveform comparison is valid →
Explore the GM timing guides

Source and limits

Original GoTech article, 2021-02-11. Illustrations retain their source descriptions; their technical meaning has not been independently reviewed. Videos and articles remain separate evidence.

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