Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Accumulating PCM Data

PCM data can be accumulated in a number of ways. This includes circuit measurements with a multimeter or NGS PID data. Acquisition of PCM PID data using the NGS Tester is one of the easiest ways to gather information. Gather as much data as possible when the fault is occurring to prevent improper diagnosis. Data should be accumulated during different operating conditions and based on the customer description of the intermittent fault. Compare this data with the known good data values.

This will require recording data in four conditions for comparison: 1) KOEO, 2) HOT IDLE, 3) 48 kph (30 mph) and 4) 89 kph (55 mph).