P0462 (fuel sender unit volts too low) and P0463 (fuel sender unit volts too high)?

shawn.fournier

shawn.fournier

New Member
Joined
Mar 28, 2022
Messages
8
Location
Kihei HI
Fuel gauge randomly surges from empty to full. Occasionally (and unexpectedly) feels like running out of gas; smells like gas and/or exhaust; generates back flow (backfire) and then, loses power and dies. Recently pulled codes P0462 (fuel sender unit volts too low) and P0463 (fuel sender unit volts too high). On my way home yesterday, “check gauges” came on and battery indicator dropped. When I got home, checked battery posts and grounds – all good… but dead battery (approx 1 yr old). Where would you start troubleshooting? Thx!!

Fyi… recent maintenance includes:
- New manifold / head gasket
- New fuel pump
- New throttle body kit
- Replaced TPS, MAP, IAC, CPS sensors (all Mopar)
 
Disconnect the (3) PCM 32 pin harness connector from PCM receptacles and check the pins/clips for oxidation; firmly snap the harness connectors into the PCM receptacles.
Inspect PCM communication split wire loom that runs along the firewall which is routed near the threaded head stud (right rear corner of head); this threaded head stud is known to wear thru the split wire loom exposing the copper strands of the wiring which will short communications to ground.
Inspect the wiring harness and connector for the fuel pump; look for oxidized wiring connections and wires that are worn thru touching the ground.
 
Make sure to check the pigtail for the fuel pump. I replaced that after months of no gas gauge and 3 fuel pumps and it did the trick.

Good luck!
 
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