2008 ford escape "Stop Safely Now" with the red triangle in and no engine codes in.
My solution to the repeated failures of the stock and aftermarket ford inverter cooling pump causing the gas engine to shut off unexpectedly.
To verify it is the inverter cooling pump that failed:
Take the return line off of the tank return slipstream and turn the key to on but without the engine running. Check for flow. No flow = dead pump. (usually a failure of the micro components on the pump's control board but I degress.) Low flow equals bad pump.
Problem background:
The inverter cooling (MEK, aux cooling pump) pump is supposed to run whenever the key is turned on. This removes heat from the inverter and the electric motor control cktry. The electric motor control cktry has a high temp cutoff limit. When this limit is reached it turns off the gas engine so as not to charge the battery anymore. This is because they tied the inverter control cktry high temp alarm/cutout into the battery thermistor temp high, battery overcharge protection gas engine cutoff.
This is very confusing to diagnose with no codes. But not once you know where to look.
The inverter cooling system is a closed-loop system. For most short trips (non-highway) the coolant has enough natural circulation cooling to stay below the electronic control cktry's high temp limit.
On long highway drives (or shorter ones after some city stop and go) the trip temperature is reached as the system's heat into the cooling loop is greater than the natural circulation's ability to remove it. Thus the seemingly random shutoff of a perfectly good running gas engine on the highway. Usually with a truck right behind you.
The codes go away when the factory bulletin's steps are followed: put the car in park, pull the key, wait 60 or more seconds, then restart and your able to drive again. That is until the electric motor control cktry reaches its high temp cutout and your back to square one. Ie the more time you wait till you restart the cooler the electronics and their cooling loop get. Which means the longer you can drive before getting the "stop safely now" gas engine shutoff.
Yes, the design is asininely stupid: shut off the gas engine for a loss of cooling on the electric one. But it is due to where the Ford engineer tied the high temp shutoff to. Instead of giving it its own high temp warning and electric motor shutdown (the logical thing to do) the ford engineer took a shortcut and tied it to the traction battery's over-temp protection gas engine cutoff. (also with no codes most of the time.) (Someone should fire that engineer for plain stupidity).
Unlike Toyota, Ford was overly concerned with the battery granadeing hence the 3 thermisters per layer, the battery high temp gas engine cutoff, and the over use of battery casing bolts and internal parts lanyards. Ford shuts down the gas engine to prevent it from charging the battery as the most likely source of high battery temp is overcharging.
Toyota was more correctly concerned with battery condition monitoring so they avoided this stupidity and provided actual battery condition monitoring to the driver. Ford provides no battery monitoring at all.
The problem with the Ford and its aftermarket pumps (apparently all made in the same place in china) is the undersized microelectronics which overheat (and burnout) from being on whenever the key is on and from pumping hot water all day long. My last ford pump lasted 41 days. (Rock Autoparts gives a 30 day warranty with the pump.) (Before finding this solution, I had replaced this pump 3 times, and I bought 3 more from the junk yard only to find them all dead.)
The solution that works:
Replace the Ford inverter cooling pump with another one from a different car company. Preferably one associated with quality and long-lasting parts. Toyota's 2008 Prius inverter cooling pump is close enough that with a little modification it makes a reliable replacement.
The Toyota brand 2008 Prius inverter cooling pump is available stock on EBAY for around $53.00.
The pump is better made with a bigger motor and higher flow rate. Its also made to handle the heat generated from constant running.
The pump is close enough in input / putput pipe size that a few wraps of electrical tape (pulled tightly when applied) and screw hose clamps will make the Ford hoses fit without leaking.
The Prius inverter cooling pump is set up to be installed horizontally.
Thus you must make a new metal backing plate and weld it to the ford pumps mounting plate. so that the Prius pump is in the same verticle alignment as the original Ford pump.
Next a trip to the junkyard is in order as you will need the Prius wiring harness plug to replace the Ford wiring harness plug.
The 2008 series Prius inverter cooling pump is located under the left front headlight. Cut the plug witing as high back as you can. (close to the harness so you have the most wiring possible from the plug).
Cut the Ford Escape inverter cooling pump plug wiring as close to the plug as you can.
Replace the Ford escape plug with the Prius one you just got.
Verify power (12 v dc) at the newly wired plug. Connect the pump to verify it turns on. (you may have to swap the wiring connection around as the wire colors are different so don't tape up the wire nuts or solder them until verification is done).
Now connect the hoses (1" hose clamps if I remember correctly) then use the original ford escape bolts to tighten the plate to the bumper mount. Make sure the ground is attached to a clean bare metal spot.
I cleaned the plate up around the bolt holes (on both sides) and put a loop end on the ground wire so that it is under the head of the mounting bolt.
With everything reconnected and bolted up fill the reservoir up to the bottom "need to fill" line. This way when you turn the key you can see the return flow (look through the fill port) Yes the level will go down when you turn the key so be ready to fill once you have verified the flow.
Now turn the key to on without the engine running. you should hear the pump running and be able to verify flow. Once flow verification is completed top off the tank and replace the cover.
Turn the key off and tape up the wire nuts so they are waterproof and you're done.
Take a long highway test drive and enjoy.
No codes at all on my standard code reader.
Red Triangle of death. No codes will show up on basic code readers. Have to select the Ford OEM Enhanced codes on the Orilies one to see any codes.
Orilies but normal code selected.
These will show once you select the Ford OEM enhanced section on the Orilies code reader. If you do not then no codes is all you see.
The electric motor control box supply and return.
2008 Toyota Prius inverter cooling pump.
It's a bigger pump and motor. Better designed to take the heat and constant running. Plastic input and out put lines are slightly smaller so wrap in electric tape very tightly to increase the diameter. Use screw hose clamps to ensure no leakage.
the plug you need to match from the junkyard.The Ford inverter cooling pump that failed.
very small impeller
The burnt circuit board. The cause of the repeated pump failures.
Way too small. It should be bigger than the Prius as the ford inverter and electric motor is bigger. Bigger means more heat.
How I modified the original bracket.
hose clamps on the intake
Wire nuts to connect the new Prius plug. Plus a better view of the bracket. (just a square piece of flat steel from Menards.)
Prius wiring plug.
A better view of both hose clamps the intake could fit 2 so it got 2 the output only has one, its shorter. The pump is running in this photo and no leaks from the hoses.
I bought my pump on e-bay. Here is an Ebay ad with the same part number.
the Toyota Prius box part number.
same just another view in case one picture goes bad.