Suzuki Keyless Start: How It Works, Fob Battery, and the Passcode Emergency Start When the Fob Is Lost

Suzuki's Keyless Start System is a dealer-installed option that starts the motor through a key-fob in your pocket instead of a mechanical key. The fob has to be within 1 m (about 40 in) of the keyless control unit, an unregistered fob will not start the engine, and if the fob is lost or its battery is dead you get in with a passcode. Which procedure you use depends on what is at your helm: boats with a main switch and a small emergency key use a 4-digit passcode entered by counting buzzer sounds; boats with an engine switch and a multi-function gauge use a 6-digit passcode typed on the gauge. Both are below, step by step, with the time windows and lock-outs the manuals print.

This guide uses the owner's manuals we have for the DF100A/DF115A/DF140A (2016 manual), DF150A/DF175A/DF200A, DF150AP/DF175AP/DF200AP, DF115B/DF140B, DF115BG/DF140BG, DF250AP/DF300AP and DF300B/DF350A, plus the registration notes in Suzuki's dealer set-up manuals. The DF75/DF90A owner's manual does not print the system: "Refer to the Keyless Start System Operation Manual packed in the product." Every manual says the same about fitting it: "Please consult with a Suzuki Marine Dealer for the installation of the Keyless Start System."

Which Suzuki outboards offer keyless start

In every manual the keyless section is headed "If equipped": it is an option, never standard. The manuals describe two versions of the system, and yours tells you which one you have.

Motors without the option use a conventional ignition key: "Turn until the ignition key is in the ON position. Turning the ignition key to the START position automatically starts engine." Those are the motors the 37141-98LA0 ignition key is for; it is not the emergency key of a keyless system.

How it works day to day

The fob

"Press and hold the lock button on the key-fob for more than one second to switch between ON mode and OFF mode." In ON mode the system can be used; in OFF mode it cannot. A brief press in ON mode makes the LED flash once, a quick way to confirm the fob is alive. The fob "uses a weak radio wave that is susceptible to external influences," so it may not work when it "is in contact with or covered with a metallic object," and because it "is always in transmission mode," its battery "may run down quickly if it receives strong radio waves from televisions or personal computers."

Main switch models (DF100A to DF140A 2016 manual, DF150A to DF200A, DF150AP to DF200AP)

With the fob in range, "turn the main switch to the ON & OFF position and then release it"; it springs back to PUSH START/STOP. "The buzzer sounds twice to notify that the Keyless Start System has been turned ON." If it "fails to turn ON, the buzzer emits one (1) long sound and five (5) short sounds"; repeat. Do not keep flicking the switch: "if the operation in the above step (2) is performed continuously, it is regarded as a theft or tampering and the main switch operation will not be accepted until a certain period has elapsed." No manual prints that period.

To start, push the main switch (the START & STOP switch on the AP models). One press turns the starter "for 4 seconds continuously until the engine starts" on the DF100A to DF140A and DF150A to DF200A, and for 3 seconds on the DF150AP to DF200AP; continuous starter time is set at five seconds, then "wait about ten seconds for the motor to cool down and try again." On twins, turning one engine's system ON or OFF does the same to the other. Turn it OFF when you are done: "if the Keyless Start System is in ON state while the engine is not running, the battery will be discharged." Trim with the system OFF differs: the 2016 DF115A/DF140A manual says the remote power trim and tilt switch still works, while the DF150AP manual says "the tilt up and tilt down switches cannot be activated when the Keyless Start System is in OFF state."

Engine switch models (DF115B/DF140B, DF115BG/DF140BG, DF250AP/DF300AP, DF300B/DF350A)

One switch does everything: "Quickly press the engine switch to start and stop engine. (The buzzer sounds once.) Press and hold the engine switch for at least 2 seconds to set the Keyless Start System ON state and OFF state. (The buzzer sounds once.)" A quick press from OFF turns the system ON and starts the engine in one go. If it "fails to turn ON, the buzzer emits one (1) long sound and three (3) short sounds"; repeat. Continuous starter time is set at four seconds; the DF140B manual says to wait about ten seconds before trying again.

The DF115BG/DF140BG, DF250AP/DF300AP and DF300B/DF350A manuals add three things the DF115B/DF140B manual does not print: holding the engine switch for at least 2 seconds while the engines run shuts them all off and turns the system OFF (the DF250AP and DF300B manuals also give a 3-second hold that turns it OFF; the DF250AP adds that the buzzer gives one short beep); pressing the lock button on the fob turns it OFF and "the buzzer sounds three times"; and "Keyless Start System automatically changes to OFF state 15 minutes after the engines are shut off." Still, "always turn the Keyless Start System to OFF state when the engine is not running," because the battery will be discharged. Two trim notes: the DF140B manual warns that the side-cover PTT switch "can be accidentally activated when the Keyless Start System is in OFF state, resulting in injury," while the DF250AP and DF300B manuals say the tilt switches "cannot be activated when the power off."

Fob battery

Every manual that prints a type says "Lithium disc type battery: CR2025 or equivalent," with a life of "about two (2) years, which can vary depending on use." When it runs low, the red CHECK ENGINE lamp flashes on the DF100A to DF140A and DF150A to DF200A, "Remote Key Battery Low" appears on the DF150AP to DF200AP gauge, and "Keyless FOB Battery Low" appears on the gauge of the DF115B/DF140B, DF115BG/DF140BG, DF250AP/DF300AP and DF300B/DF350A.

Replacement, as printed for the DF140B and DF250AP: "Insert a flat blade screwdriver in the slot of the keyless fob and remove the cover. Remove the O-ring. Insert a flat blade screwdriver into the slot at the mark on the cover to remove the battery. Replace the battery so its + terminal faces the cover side as shown in the illustration," then "confirm that the O-ring is placed in position on the body side." The DF300B/DF350A manual prints no battery type and says "be sure to ask your authorized Suzuki Marine Dealer to replace the battery." The newer manuals carry the coin-cell warning: "If swallowed, the coin/button cell battery can cause severe internal burns in just 2 hours and may lead to death." And "do NOT attempt to disassemble, repair, or modify the keyless fob."

Spare fobs, registration and the ECM pairing

"Two (2) key-fobs are supplied with the Keyless Start System" and "a maximum of six (6) key-fobs can be registered in one keyless control unit." Adding one is dealer work. The set-up manuals say "Register one key-fob at a time," that "two keyless fob ID codes must be registered" before the system will operate at all, and, for the DF115B/DF140B, that "the registration cannot be deleted." During registration the fob being paired sits "less than 0.3 m (12 in) from the keyless control unit" while the other is kept "more than 1 m (3.2 feet)" away; the installer pushes the engine switch, presses the fob button "within 10 seconds" of its red LED lighting, and the LED blinks for 3 seconds on success. A power cycle finishes it: "After 30 seconds, operate the engine switch again and turn on the power to complete the ECM keyless registration." The older DF115A/DF140A and DF70A to DF100B systems need "a laptop computer with the Suzuki Diagnostic System version 8 or later and hardware version 5 or later" (version 8.30 in the DF70A manual); the control unit is part number 37171-96L01 or 37171-96L11. What the SDS tool is and why dealers need it is in the SDS diagnostic system explainer.

On the gauge models the dealer also has a dealer passcode for the Keyless Setting menu: "If you enter the wrong dealer passcode 3 times in a row, the Keyless Setting cannot be selected. You can select it by turning on the system again. After the power ON, please select Keyless Setting within 30 seconds." Until the owner passcode is changed from the factory default, "the message Change the default passcode is displayed each time the power is turned on." Change it before you need it.

If you are buying used: "Once an ECM has been connected and paired to a keyless start control unit, the ECM/outboard cannot be started with a normal key switch," and if the system is removed or the ECM swapped without unpairing, "the removed ECM without unpairing will be unusable." If a fob goes missing, "immediately contact your authorized Suzuki Marine Dealer"; the same applies "if the key-fob and the emergency key are lost."

Emergency start when the fob is lost or dead

4-digit passcode by buzzer count: DF150A/DF175A/DF200A, DF150AP/DF175AP/DF200AP, DF100A/DF115A/DF140A

"If the key-fob is lost or the key-fob battery has run low, the Keyless Start System OFF (locked) state can be released by using the emergency key and entering the 4-digit passcode." Two things have to be in place first. The emergency key: with a side mount remote control box "one (1) emergency key is included in the remote control box," with a top mount box it "is included in the main switch panel," and it "should be carried separately from the key-fob to avoid losing both of them at the same time." And a passcode, which can only be set with a working fob in range, so "carry the passcode with the emergency key in case the key-fob battery runs down or the key-fob is lost." Setting it is a main-switch sequence: the buzzer "emits one (1) short sound for the 1st digit, two (2) short sounds for the 2nd digit, three (3) short sounds for the 3rd digit, and four (4) short sounds for the 4th digit," you pick each digit by turning the switch after that many sounds ("to set or select zero (0), turn the switch after the 10th sound"), and after the fourth digit you have 60 seconds to "turn the switch ON and hold it for five (5) seconds until the buzzer stops." Then "do not perform any operation for at least 30 seconds, while the system performs passcode update." Run it twice and "the last passcode entered will become effective."

The emergency start, in the DF150A/DF175A/DF200A manual's numbering (the DF150AP and 2016 DF115A manuals print the same sequence; on the AP models the final start is the START & STOP switch):

1. "Turn the main switch to the right about 15° and pull it out."
2. "Insert the emergency key into the key cylinder." (The manual's step 3 is not in our extraction; follow the printed sequence in your manual.)
3. Step 4: "Turn the emergency key to ON & OFF position, and then release it to the PUSH START/STOP position. The buzzer emits one (1) long sound and five (5) short sounds."
4. Step 5: "Pull out the emergency stop switch lock plate."
5. Step 6: "Turn the emergency key to the ON & OFF position and hold it until the buzzer sounds. Turn the emergency key back to the PUSH START/STOP position. The system turns to stand-by state for passcode input."
6. First digit: "When the buzzer sounds for the same number of times as the 1st digit of the passcode, immediately turn the emergency key to the ON & OFF position, and release it to the PUSH START/STOP position. To enter 0 in the passcode, turn the switch after the buzzer sounds 10 times."
7. "After an 11th long sound, repeat" the count-and-turn "to enter the second, third and fourth passcode digits."
8. "Turn the emergency key to the counterclockwise within 10 seconds after entering the 4th digit of the passcode. The buzzer emits two (2) short sounds when the passcode input is successful, and the engine can then be started."
9. To start: "Install the lock plate on the emergency stop switch. Make sure the motor is in NEUTRAL. Push the emergency key to start the engine" (DF150A to DF200A) or "Push the START & STOP switch to start the engine" (DF150AP to DF200AP).

The rules: "If the emergency key is not operated within 10 seconds, the buzzer sounds five (5) times followed by another beep, and the input operation is cancelled. In this case, repeat the procedure beginning at Step 2." "If a wrong passcode is entered or the input operation fails, the buzzer emits a long sound after entering the 4th digit followed by three additional beeps, and the operation is cancelled." "The input operation is cancelled if no entry is made after repeating the passcode input operation three (3) times," signaled by three buzzer sounds. Once in, "the passcode authentication state is maintained for 15 seconds after turning the emergency key to the PUSH START/STOP position. In this state, the engine can be started by turning the emergency key to the left and pressing the main switch." On twins, "by carrying out the emergency start operation on either one of the engines, another engine may be started by operating the main switch." These manuals print no wrong-passcode attempt limit; the only lock-out is the tamper hold on the main switch described above.

6-digit passcode on the gauge: DF115B/DF140B, DF115BG/DF140BG, DF250AP/DF300AP, DF300B/DF350A

"If the keyless fob cannot be used due to a dead keyless fob battery or other issue, you can start the engines without the keyless fob by entering the passcode in the multi-function gauge." None of these manuals mentions an emergency key; the gauge is the way in. The sequence, in the DF140B wording (the BG, DF250AP and DF300B manuals print the same steps):

1. "Pressing engine switch causes Check Keyless FOB to appear on the screen. The buzzer will be triggered with one long beep followed by 3 short beeps."
2. "Enter Passcode? appears when any button in the gauge is pressed. To enter the passcode, use the up or down button and then select Yes. Then, press the SET button to proceed to the Enter Passcode entry screen. (Selecting NO turns the system off.)"
3. "Enter a 6-digit passcode. Use the up or down buttons to select a number for each digit. Press the SET button to move to the next digit. Press the MENU button to return to the previous digit."
4. "If the entered digits matches the 6-digit passcode, pressing the SET button will display the normal screen"; the system is now unlocked.
5. To start: "Make sure the motor is in NEUTRAL" (the manual's step 6 is not in our extraction), then "quickly press the engine switch to turn the starter motor and start engine."

Two hard limits are printed. "If you select yes for Enter Passcode?, you must complete the entry within 5 minutes. After 5 minutes, the power turns off." And "If you enter the wrong passcode 5 times in a row, the keyless start system automatically powers down the keyless start system and does not accept a passcode for 30 seconds." With a working fob in range you can view or change the passcode from the gauge menu ("You can display the Keyless Start System passcode. You can also change the passcode"): press SET under Passcode Setting and enter a 6-digit code the same way. Without the fob, "when the keyless start system starts up, enter your passcode, and you can change it within 1 minute after unlocking."

DF75/DF90A and the DF70A to DF100B service manual

The DF75/DF90A owner's manual gives no procedure; its keyless and engine switch entries both say "Refer to the Keyless Start System Operation Manual packed in the product," and add that "the SUZUKI KEYLESS START SYSTEM is available from your authorized Suzuki Marine Dealer." The DF70A/80A/90A/100B service manual confirms only the basics: "The engine can be started without operating a mechanical key when the key fob is located within a 1 m (39.3 in) radius of the keyless control unit," and its 2022 supplement mentions a 15-minute automatic shut-off and an engine stop by pressing the engine switch quickly three or more times within one second, or holding it three seconds or more. For these motors the operation manual packed with the kit is the only printed source for the passcode procedure; your dealer can supply it.

Warnings the manuals repeat

• Pacemakers. "Radio waves from the keyless control unit may interfere with the operation of electrical medical equipment such as pacemakers. Anyone who uses electrical medical equipment such as a pacemaker should consult the medical equipment supplier." The set-up manuals put a distance on it for the installer: "do not let the pacemaker or ICD come within 22 cm (9 in) of the keyless system transmitter."
• Other radios. "The radio waves emitted from the key-fob may cause interference with other wireless communication devices such as mobile phones and remoter controllers. Do not operate the buttons on the key-fob more than necessary." Installers are told to "install navigation and other equipment more than 50 cm (20 in) away from the keyless control unit."
• Flying. "The key-fob emits radio waves that may interfere with aircraft operations. Do NOT operate the buttons on the key-fob while you are in flight. When putting the key-fob in a bag, etc., protect the buttons from accidently being pressed."

Troubleshooting: the motor does not see the fob

The keyless system has three caution triggers of its own, shown the same way as the family's other alarms: on lamp models "the red CHECK ENGINE lamp will flash"; on gauge models "Check Keyless FOB" (or "Check Remote Key" on the DF150AP to DF200AP) and a caution alarm icon appear. The rest of the lamp and gauge alarms are in the warning light and buzzer guide.

No owner's manual we have prints a separate fuse for the keyless control unit itself. Anything past these checks, including a fob that will not register, a system that stays locked after the correct passcode, or an ECM moved between motors, is dealer work with the SDS tool; check with your dealer first if the motor is under warranty.

Parts for this job

Switch panels, main switches, emergency stop switches and keys are in the Suzuki OEM switches and keys collection; multi-function gauges and their harnesses are under gauges and instruments. The 37141-98LA0 ignition key is for motors with a conventional ignition key switch only. Keyless control units and fobs are dealer-supplied and dealer-registered; have the model code and serial number from the ID plate ready when you call. Orders over $149 ship free to the lower 48.

Sources: Suzuki owner's manuals for DF100A/DF115A/DF140A (99011-90J70-03B), DF150A/DF175A/DF200A (99011-96LC0-03B), DF150AP/DF175AP/DF200AP (99011-96LD0-03B), DF115B/DF140B (99011-99L30-03B), DF115BG/DF140BG (99011-99L20-03B), DF250AP/DF300AP (99011-98JB0-03B), DF300B/DF350A (99011-98L60-03B) and DF75/DF90A (99011-87LC0-03B); Suzuki set-up manuals 99505-92J20-01E (DF115A/DF140A), 99505-87L50-01E (DF70A to DF100B), 99505-99L40-01E (DF100C/DF115B/DF140B), 99505-96L60-01E (DF150A/DF175A/DF200A) and 99505-98J40-01E (DF250AP/DF300AP); Suzuki service manual 99500-87L10-01E with supplements (DF70A/75/80A/90A/100B). Figures are Suzuki's published values; confirm against the manual for your model year and serial number.