P1804

DTC P1804: Shift Fork Position Sensor 1 and 2 System (Power supply voltage low range out)

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

DIAGNOSTIC FUNCTION
TC-SST-ECU checks that the supply voltage to the shift fork position sensor 1 and 2 is normal.

DESCRIPTIONS OF MONITOR METHODS
The supply voltage to the shift fork position sensor 1 and 2 is too low.

MONITOR EXECUTION
^ Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC, stored in memory for the item monitored below)
^ P1820: Shift fork position sensor 1 system (voltage low range out)
^ P1821: Shift fork position sensor 1 system (voltage high range out)
^ P1822: Shift fork position sensor 1 system (Output range out)
^ P1824: Shift fork position sensor 1 system (Poor performance)
^ P1825: Shift fork position sensor 2 system (voltage low range out)
^ P1826: Shift fork position sensor 2 system (voltage high range out)
^ P1827: Shift fork position sensor 2 system (Output range out)
^ P1829: Shift fork position sensor 2 system (Poor performance)
^ P1836: Shift fork 1 malfunction
^ P183D: Shift fork 2 malfunction
^ P1844: Shift fork 3 malfunction
^ P184B: Shift fork 4 malfunction
^ P1852: Shift fork 1 or 2 opposite direction movement
^ P1855: Shift fork 3 or 4 opposite direction movement
^ P1857: Odd number gear axle interlock
^ P1858: Even number gear axle interlock
^ P1876: Gear block 1st
^ P1877: Gear block 2nd
^ P1878: Gear block 3rd
^ P1879: Gear block 4th
^ P187A: Gear block 5th
^ P187B: Gear block 6th
^ P187C: Gear block reverse

Sensor (The sensor below is determined to be normal)
^ Shift fork position sensor 1
^ Shift fork position sensor 2

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.

JUDGMENT CRITERIA
^ Supply voltage: 3.07 V or less. (140 millisecond)

OBD-II DRIVE CYCLE PATTERN
The supply voltage remains 3.07 V or more for 140 milliseconds.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of shift fork position sensor 1 and 2

DIAGNOSTIC PROCEDURE

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Check the TC-SST-ECU power supply circuit
Inspection Procedure 4: TC-SST-ECU Power Supply Circuit Malfunction
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the TC-SST-ECU power supply circuit. After repairing the power supply circuit, go to Step 3.

STEP 3. Check whether the DTC is reset.
Q: Is DTC No. P1804 set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.