Code
P1432
HUMMER
P — Powertrain
Fuel Level Sensor 2 Circuit Low Voltage
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring in fuel level sensor 2 circuit (short to ground)
- Poor or corroded connector at the fuel level sender/module
- Failed fuel level sender or sender float/mechanism
- Bad ground or low reference (5V) supply to the sender
- Blown fuse or relay feeding the sender circuit or module
- Water intrusion or contamination in the tank module
Symptoms
- Fuel gauge reads empty or lower than actual level
- Erratic or intermittent fuel level readings
- MIL (check engine light) may be illuminated
- Possible fuel range/warning messages on dash
- No effect on engine running in most cases (vehicle usually still runs)
What to check
- Scan for freeze-frame and pending/complementary DTCs
- Visually inspect wiring and connectors at both fuel tank(s) and under-hood junctions
- Check related fuses and relays for the fuel level sender/module circuit
- Backprobe the sender connector with key ON to measure voltage and signal
- Wiggle test harness to try to reproduce the code
Signal parameters
- Expected signal type: variable voltage or variable resistance to ECU depending on model
- Typical voltage range (model-dependent): ~0.5–4.5 V across tank range at sender signal pin with key ON (not charging)
- Reference supply typically: 5 V or ignition-switched supply — should be stable at the connector
- Sender resistance ranges vary by sender design; consult vehicle-specific spec for ohms-at-empty/full
Diagnostic algorithm
- Retrieve freeze frame data and note conditions when the code set (fuel level, ignition state, battery voltage).
- Inspect visible wiring and connectors for damage, corrosion, or water entry at the tank(s) and along the harness. Repair as needed.
- Verify fuses/relays supplying the sender/module. Replace any blown fuses and retest.
- With key ON (engine off), backprobe the fuel level sensor 2 signal, ground, and reference pins at the tank connector. Measure signal voltage and reference voltage. Compare to expected ranges.
- If signal is low (near 0 V or significantly below expected), disconnect the sender and measure continuity to ground to check for a short to ground. Also check for open circuit to ECM.
- Measure sender resistance directly at the sender (if accessible) while moving the float or with tank at a known level, and compare to manufacturer spec.
- If wiring harness and sender check good, verify the PCM/BCM input pin for open/short at the module connector. If possible, perform a substitution or use a known-good module per service procedures.
- After repairs, clear codes, perform key cycles and a short drive to confirm code does not return and fuel level reporting is normal.
Likely causes
- Open/shorted harness or damaged insulation to sender (most likely)
- Corroded/loose connector at fuel tank module or sender
- Failed sender assembly (worn resistor, broken float)
- Poor ground or low reference voltage due to blown fuse or bad splice
- Less likely: module/ECM fault
Fault status
Status
P1432 — Fuel Level Sensor 2 Circuit Low Voltage: the control module detected a lower-than-expected voltage on the fuel level sensor 2 circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Repair manuals
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138
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