Free API
Back to 2007 Ram 3500
Help
2007 RAM 3500
5.9L I6 Cummins•4WD•diesel•ISB•turbo
1 active safety recall on this vehicle — view recalls🏆Sponsored by Timmehster
Repairs487Labor523Torque138Fluid11DTC1714Battery1Maintenance0Recalls1
P0840moderate severityPowertrain

Transmission Fluid Pressure Sensor/Switch A Circuit

on 2007 Ram 3500 5.9L I6 Cummins · 4WD

What this code means

The PCM detected a problem in the transmission fluid pressure sensor or switch circuit A. This can cause incorrect line pressure readings and affect shift quality.

Symptoms

  • Harsh or erratic shifting
  • Transmission warning light on
  • Possible limp mode

Common causes

  • Faulty transmission fluid pressure sensor
  • Damaged wiring or connector
  • Low or dirty transmission fluid
  • Internal transmission pressure fault

Diagnostic steps

  1. Scan for codes and check freeze frame data
  2. Check transmission fluid level and condition
  3. Inspect sensor wiring and connector
  4. Test sensor resistance and compare to spec
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITE
Shop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Other Powertrain codes on this vehicle

🔌 Need this data in your app? It's all in the free API →
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years. Spot an error? Use the Help link above — a human reads every report.
Stuck on this repair? Take it to The Diag Desk — ask a master tech about this exact car → real human answer within 24h, never AI
Share:XRedditFBWhatsAppThreadsEmail
🔓 LIBERATED FOREVER
The 2007 Ram 3500 5.9L I6 Cummins repair data is free for every DIYer and shop on earth, permanently, because Timmehster paid $99 to unlock it.
Mitchell1 charges $169/mo for this. ALLDATAdiy charges $30/yr per vehicle. Open Labor Project is free permanently, because of community sponsors like Timmehster.
Free another vehicle →
Building an app?
Free API access to all this data — 10 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →