Hyundai Elantra speed sensor diagnosis
The 2007-later Hyundai Elantra uses two individual sensors to detect the rotational speed of the transaxle’s input and output shafts. The part descriptions as “Input” and “Output” are based upon their use in previous Hyundai models. However, the sensor applications are reversed for the 2007-later Elantra. The two sensors are not interchangeable.
P/N Description Function in 2007-later Elantra
42621-39200 Output speed sensor Input speed sensor
42620-39200 Input speed sensor Output speed sensor
NOTE: When diagnosing DTCs for either of these sensors for 2007-later Elantras, the part numbers from the above table should be referenced. Disregard the parts description in the parts catalog.
1. Attach a GDS and select vehicle, “A/T,” “Current Data” and “Input speed sensor” and “Output speed sensor.” If the sensors show continuous/changing output, the wiring has no open/shorts during the current test condition. Proceed to Step 2.
2. Check the wiring harness visually for an open circuit or short circuit to ground.
3. Disconnect the connectors at the input and output speed sensor and PCM. Check for bent pins or pins not fully inserted into the connector. Check the pin tension using the J-35616-C Pin Tension Tester. If a harness open/short is found, repair or replace the ECM control harness between the PCM and transaxle. If a harness open/short is not found, proceed to Step 4 or 5.
4. For the following DTC(s), replace the input sensor P/N 42621-39200:
P0715 (input speed sensor circuit)
P0716 (input speed sensor range/performance)
P0717 (input speed sensor no signal)
5. For the following DTC(s), replace the output speed sensor P/N 42620-39200:
P0720 (output speed sensor circuit)
P0722 (output speed sensor no signal)
6. Attach a GDS and clear the codes. Drive the vehicle for two key-on to key-off cycles. If the DTC(s) do not set again, return the vehicle to the customer. If the DTC(s) do set again, substitute a known good PCM from another 2007-later Elantra and test drive for two key-on to key-off cycles. If the condition is corrected, replace the PCM. If not, proceed to Step 7.
7. If Steps 1-6 do not correct the condition, troubleshoot the harness for an open/short circuit. Repair or replace the ECM wiring harness between the PCM and the transaxle, if necessary.