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2002 Hyundai Accent 1.5L P0103 MAF Sensor Fault: High Voltage Issue Despite Replacement

Model: 2002 Hyundai Accent L 1.5 Fault Code: P0103 Posted: 2015-02-07 14:52

I recently replaced the Mass Airflow (MAF) sensor on my 2002 Hyundai Accent 1.5L, but the P0103 fault code for 'MAF Sensor High Voltage' persists. Using a scan tool, I observe an airflow rate of 920 cubic feet per minute (cf/m) at idle, and the intake air temperature (IAT) sensor reads -40°F — both values are significantly outside normal operating ranges. The MAF wiring harness has been inspected thoroughly: all wires are intact, connections are clean and securely seated, and there are no visible faults along the route to the Engine Control Module (ECM). Despite this, the issue remains unresolved. I'm seeking advice on what steps to take next — could it be a faulty sensor, incorrect reference voltage, or an internal circuit problem? Additionally, the IAT reading of -40°F suggests that the Powertrain Control Module (PCM) is not detecting any temperature change, which may indicate either an open circuit in the IAT sensor or a failure in the signal path to the PCM. Any insights or diagnostic suggestions would be greatly appreciated.

Related fault codes
P0103
Comments (4)
Anonymous 2015-02-08 08:37

Verify the voltage levels on the MAF sensor circuit using a multimeter. Ensure proper reference voltage (5V) and ignition positive (12V) are present at the connector.

Anonymous 2015-03-30 05:44

When the MAF connector is unplugged, the 5V reference voltage reads normally (5V), ignition (+) shows 12V, and the IAT wire has 5V. However, when the connector is reconnected, the 5V reference on the MAF circuit jumps to 10V, and the MAF signal voltage rises to 12V — which is far above the expected range of 1–2V at idle. The ignition (+) remains stable at 12V.

Anonymous 2015-04-01 22:40

The voltage readings with the MAF sensor plugged in are concerning. When unplugged, the voltages appear normal — though I don't have access to the official wiring schematic for verification. Does your original MAF sensor produce similar abnormal readings when reconnected? The IAT reading of -40°F indicates that the PCM is not detecting any temperature change, suggesting either an open circuit in the IAT sensor or a broken signal path between the sensor and the PCM.

Anonymous 2015-04-04 18:34

To properly diagnose this issue, using an oscilloscope to monitor the MAF signal waveform is recommended. This will help identify whether the problem lies with the sensor output, wiring, or signal integrity at the ECM level.