Diagnose Ford Escape No Start
Where to begin when you have a Ford Escape no start condition
Ford uses an antitheft system to tell the PCM to energize a starter relay located in the battery Junction box. The image shown here is from a 2008 Ford Escape, Mercury Mariner. So your first job is to find out whether the no start problem is due to a bad relay or some other component or wiring harness. The easiest way to test the starter relay is to locate it in the battery junction box and find another relay in that same junction box that has the same part number or same size and swap the relays. If the engine starts, you’ve nailed it down to a bad starter relay. If not, you’ll want to check for power going to the starter relay contacts and the relay control coil.
How to test for starter relay power
Grab your voltmeter and yank the starter relay. You’ll be testing the terminals in the relay socket. Look at the bottom of the relay to find the terminal number and locate those same terminals in the socket. With the key turn to the START position, you should see battery voltage on terminals 2 & 3. If you don’t get battery voltage on those terminals, check fuse #11 30A (again, this is a 2008 Ford Escape—yours might be different).
In this case, power flows from the battery to the IGN switch. Then it flows to the transmission range selector (the park/neutral switch) and then to terminals 2 & 3 in the relay socket. If you see battery voltage on those two terminals, check for ground on terminal 1. If the anti-theft system passes, the PCM provides ground to the control coil on terminal 1. If you get ground, the PCM and antitheft are working.
No power at the starter relay
If you don’t see battery voltage at terminals 2 & 3, check the gray/violet wire at the IGNITION switch when turned to the START position. If there’s no power on the gray/violet wire, replace the IGN switch. This is a fairly common failure.
No power on the starter relay control coil ground
If you don’t see good ground on terminal #1 in the starter relay socket, that means the PCM isn’t getting power or the anti-theft system has passed. In that case you should see the security light on.Posted on by Rick Muscoplat