Mar 12 • Diagnosis Board
Diag help needed
Need some diagnostic help from the Chrysler guys.
2016 Ram 1500 3.6 Pentastar.
Customer came in with a broken intake resonator / intake tube that was taped together. Truck had a high idle and was throwing codes.
Current codes:
- P2173 – High Airflow / Vacuum Leak Detected (slow accumulation)
- P0507 – Idle Speed Higher Than Expected
Truck is idling around 1100–1200 RPM while the target idle is ~680 RPM.
Here’s everything we’ve tested so far and why:
• Replaced intake tube / resonator because the original one was cracked and taped up (possible unmetered air source).• Smoke tested intake system to check for vacuum leaks – none found.• Cleaned throttle body – minimal carbon but cleaned anyway.• Replaced throttle body with new unit after noticing throttle position PID acting strange (showing 0). No change.• Checked wiring and pins at throttle body – all good.• Checked MAP data – showing about 67 kPa at idle.• Fuel trims basically 0 (not indicating a typical vacuum leak).• Clamped brake booster line to eliminate booster leak – no change.• Checked PCV behavior via oil cap test – no major idle change.• Pulled EVAP purge hose and blocked intake port – strong vacuum but idle did not drop.• MAF sensor and intake tube are new.
Scan data shows PCM trying to close the throttle (negative ETC duty) but RPM stays high.
At this point it seems like the engine is getting extra air after the throttle body, but we haven’t found an external vacuum leak.
Has anyone run into this exact issue on a Pentastar with these two codes and high idle around 1100 RPM?
Wondering if this could be an internal intake manifold / PCV issue or runner control problem that won’t show up on a smoke test.
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Diag help needed
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