G2: DIY: Diagnosis: Starting Issues

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Common causes and solutions for starting issues are explained here. They are in the approximate order of how commonly they occur on a Legend, with preference given to items that are easiest to test. Rather than cover every possible reason that a Legend will not crank or start, this guide will focus on common problems specific to the Legend. For further diagnoses beyond these items, you will want to test individually for air, fuel, and spark as you would with any other car. For clarification: Crank means that the battery-powered starter is rotating the flywheel, this is what happens while you are turning the key in the ignition to the final position; Start to put it simply means that the engine is now running on fuel and no longer needs the starter. Turn over is a commonly misused term and will not be used here.


Weak Battery

Rather than repeating the same information in both sections below, it will be explained here. If your battery is weak or dying, it may still crank the engine slowly, but it will never start. If the battery is very weak or completely dead, the engine will not crank at all, though you may hear a repeated clicking sound. This is the starter solenoid trying to "turn on" the starter. If you have a multimeter, test your battery voltage. It should be above 12 volts, preferably above 12.5. If it is below 12, even 11.9, you can consider the battery drained. If you don't have a multimeter, or your voltage tested low, then take the battery to your local parts store and they can recharge and test it for you.


To-Do: List of fuses that can cause a no-start issue

Engine Cranks But Does Not Start

Main Relay

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The most common reason that a Legend will crank and not start is the PGM-FI (Programmed Fuel Injection) Main Relay. The PCB (printed circuit board) inside this relay often has bad solder points, which causes the internal "switching" mechanism to fail. This relay controls (among other things) power to the fuel pump, and will prevent the car from starting if it fails. Sometimes this part will work intermittently, and sometimes it will just suddenly and completely stop working. In some cases, you can bang on the trim panel underneath the steering wheel (on the left, above the trunk release lever) while cranking, and this will "pop" the relay into place, which in turn provides power to the fuel pump and the car will start. If this works, the main relay is without a doubt failing and should be repaired (if you know how to solder) or replaced.

Another clue that the main relay is the cause of your no-start issue is the Check Engine Light (CEL). When you turn your key to IG2 (ON), which is the last spot before cranking, all of the warning lights in your instrument panel should light up for 2 seconds and then turn off. If the CEL does not turn off after 2 seconds, one of the causes is a bad main relay.

For repair information, see here: Main Relay Repair. For replacement, you can try used relays from the junkyard, where they will be relatively cheap but you will not know their condition beforehand and you may end up purchasing one that has already failed or is near failure. You can buy aftermarket relays from your local parts store. You can also get one from any Honda or Acura dealer. The OEM part number is 39400-SP0-013 for all G2 Legends, although relays from some other Hondas and Acuras are the same, though use different part numbers. It should cost no more than $70 from a good dealer (see here for a list of online OEM parts dealers: G2: FAQ: OEM Parts Guide: Where to buy new OEM parts).

Engine Grounds

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There are two essential ground wires on the engine that are often forgotten and left disconnected, both have been known to cause starting issues. One of them is on the passenger side fuel rail, this is the ground for the Ignition Control Module (ICM). The other is on the thermostat housing bolt and is the ground for a number of components, many of which are required for starting the engine.

Engine Does Not Crank

Battery Terminals

Check that the positive and negative battery terminals are clean and free from corrosion. Also check that they are both clamped down tightly on the battery. With a loose battery terminal, everything can appear to work fine when you first turn the key to ON (IG2), but then when you try to start the engine it loosens and the car seems to die. If your cables are heavily corroded or cannot be tightened any further, you may consider replacing them.

Starter Solenoid

G2 DIY StartingIssues SolenoidWire.jpg

The "trigger" wire on the Legend starter solenoid is a press-on spade fitting and does not lock in place. It is known to come loose over time and fall off, especially if you had work done in that area and could have pulled on the cable. This cable is what tells the starter that you are turning the ignition key and to begin cranking. When it falls off, the starter will not crank when you turn the key, and you will not hear a repetitive clicking sound as you hold the key. In the picture to the right: The arrow at the top (pointing down) is the disconnected wire, and the arrow on the bottom (pointing up) is the terminal on the starter solenoid where it should be connected.

Ignition Switch

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On the back side the ignition switch is the electrical portion, this is not about the entire key cylinder. After years of wear, the contacts inside can become worn out. When this part fails, it can either prevent your engine from cranking, or it will crank and start up but immediately die when you release the key. It costs around $60 brand new from the dealer. The switch and cylinder has four positions: IG0, IG1, IG2, IG3. IG0 is the first "Off" position. IG1 is "Acc", or Accessory. IG2 is "ON", and is the position the key will be in while driving, it provides power to all electrical components in the car and engine. IG3 is the final position, "Start". When you turn the key to IG3, the starter solenoid is triggered, and the battery provides power directly to the starter to begin cranking. You can test this function of the switch with a multimeter on the black/white wire in position 4 of the brown 6-pin C901 connector at the under-dash fusebox.

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Main Relay Repair
G2: FAQ: OEM Parts Guide: Where to buy new OEM parts
Old "sticky" thread on AcuraLegend.org
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