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OBD-II Code

P1682

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$40–$1,400

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

P1682 is the Driven Power 2 (also called Ignition Voltage 2 on some calibrations) circuit code — the PCM monitors a secondary switched-ignition feed (typically pin labeled IGN-E or Driven Power 2 on E40, E67, and later E38/E92 PCMs) that must be at battery voltage whenever the primary ignition feed is at battery voltage.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP1682 is the Driven Power 2 (also called Ignition Voltage 2 on some calibrations) circuit code — the PCM monitors a secondary switched-ignition feed…

P1682 is the Driven Power 2 (also called Ignition Voltage 2 on some calibrations) circuit code — the PCM monitors a secondary switched-ignition feed (typically pin labeled IGN-E or Driven Power 2 on E40, E67, and later E38/E92 PCMs) that must be at battery voltage whenever the primary ignition feed is at battery voltage. When the two feeds disagree by more than approximately 2V for over 1 second, P1682 sets.

Cheapest-first

  1. locate the PCM connector with the Driven Power 2 pin (consult the wiring diagram for the specific PCM — on E40, it's typically C1 pin 71; on E67, C2 pin 4 area) and backprobe with a DMM key-on; you should see steady battery voltage that drops with the ignition switch.
  2. If the voltage is low or absent, trace upstream to the underhood fuse block — the Ign 1 and Ign 2 fuses share a common feed but split at the bus, and a corroded fuse-block contact will pass one feed while starving the other.
  3. The expensive misdiagnosis: replacing the PCM ($1200+ programmed) when the actual fault is a green-corroded pin in the underhood fuse block.
Vehicle-specific patterns2004-2007 Silverado/Sierra/Tahoe/Yukon/Suburban 4.8L/5.3L/6.0L with E40 PCM is the classic P1682 truck — the underhood fuse block develops solder cra…
  • 2004-2007Silverado/Sierra/Tahoe/Yukon/Suburban 4.8L/5.3L/6.0L with E40 PCM is the classic P1682 truck — the underhood fuse block develops solder cracks on the Ign 2 bus, documented in PIP4055 (the fix is fuse block replacement or careful resolder).
  • 2007-2013Silverado/Sierra 5.3L/6.0L with E38 PCM sees P1682 from corrosion at the C2 connector (the gray one) where road salt enters through a poorly seated bulkhead grommet.
  • 2006-2009Trailblazer/Envoy 5.3L LH6 throws P1682 from the same fuse-block failure pattern.
  • 2008-2010Cobalt SS 2.0L Turbo with E67 gets P1682 from the underhood relay center developing high resistance on the secondary ignition relay contacts.

Estimated repair$40 to $1400.

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