The NextGen PI Sedan – PI Utility Operation and Service training is a two-day course with the same content as dealership tech training. The training is divided into six major sections: Vehicle Overview; Electrical-Electronics; Engine Operation-Components; Engine Diagnostic-Service; Automatic Transaxle; All Wheel Drive. This course is perfect for, and should be required for, police shops that go beyond preventative maintenance jobs of oil, tire and brake changes. For Part 1, go to www.hendonpub.com, then Resources, and then Article Archives.
Ti-VCT and EcoBoost
The 3.5L V6 (base) engine in the PI Sedan and the 3.7L V6 engine in the PI Utility use Twin independent Variable Cam Timing, Ti-VCT. That means all four cams are separately controlled by cam phasers and phase solenoids. (The four cams are one intake cam and one exhaust cam for both banks of the V6.) Ti-VCT, or variable valve timing, means each cam can be individually advanced or retarded (with respect to the crank and pistons) to produce the best power and the best fuel economy.
The 3.5L EcoBoost (twin turbo) V6 was discussed in detail during the course. Two important differences exist between the EcoBoost V6 and the other two police engines. The EcoBoost engine uses turbochargers and the EcoBoost engine uses direct injection.
The function of all the turbo and direct injection components were described and the location identified. For example, the direct injection uses two fuel pumps: a low pressure (65 psi) pump and a high-pressure (2150 psi) pump. Hear that subtle whir sound when the door unlock tab on the key fob is pressed? Or when the door is open and the courtesy lamp circuit is activated? That is the low pressure pump priming the direct-injection high-pressure system.
The second day was the core of the tech training. How about basic engine operation? The appropriate WSM and PC/ED service publications were pulled up. What section of the WSM describes turbocharger service procedures? Fuel Charging and Control. What is the function of the Adaptive Spark Ignition strategy? It retards ignition to prevent pre-detonation (ping). What symptom would occur if the Demand Control Valve electric circuit was interrupted, cut or disconnected? The engine will start, run and idle well, but it will not have much power.
Where is the Charge Air Cooler sensor located in relation to the throttle plate? It is upstream of the throttle plate. Do the 3.5L Ti-VCT and 3.7L Ti-VCT have a Mass Air Flow (MAF) sensor? Or a Manifold Absolute Pressure (MAP) sensor? Or both? The Ti-VCT engines have only a MAF, while the EcoBoost engine has two MAPs.
Right Oil is Critical
Engine oil has always been used as a lubricant and as a coolant. What new function does engine oil perform on Ti-VCT engines that it never did on the Ford CVPI 4.6L V8? It acts as hydraulic fluid to operate the cam phasers.
With engine oil used to operate the cam phasers, two aspects of preventative maintenance become even more critical. First, these new Police Interceptor engines MUST have the right weight-viscosity of engine oil. The PCM opens up valves to control the cam phasers based on the correct oil. Too heavy or too light and the cam phaser will over-react or under-react. The VCT phaser not responding correctly to the PCM will cause a DTC: an error in action versus expected cam advance or retard.
Exactly the same condition can occur with dirty oil, specifically oil that has depleted the anti-foam additives. Oil with tiny foam (air) bubbles is more compressible than oil with no foam. So, oil under pressure has to break these tiny bubbles before it can act as a true hydraulic fluid. That will cause a slight delay in the response of the cam phasers to the PCM command.
It won’t be much of a delay, but the PCM again monitors actual versus expected and can throw a DTC. Change the oil and the problem goes away. How about using synthetic oil? Nope. It is the anti-foam additive package that gets depleted, not the breakdown of the base stock.
The next hands-on-keyboard exercise, of course, reinforced the training on both the Ti-VCT and EcoBoost engine systems. The tech went to the IDS computer and pulled up a pre-loaded datalogger recording. This tracked 60 seconds of the operation of a 3.5L Ti-VCT (base) V6 in a PI Sedan or a 3.7L Ti-VCT V6 in a PI Utility.
What is happening on the intake VCT side? The intake cams start to advance from base line. Then what happens on the exhaust VCT side? The exhaust cams start to retard from baseline. Then what happens to the exhaust cams about 20 seconds later? It returns to baseline. What does the full VCT recording show? The police car was cruising at partial throttle, then was driven at Wide Open Throttle, then was idled.
By the way, to diagnose issues with the turbo systems, start with your ears. Do you hear a whoosh or do you hear a whistle? Remember that all turbos have a low-pressure side and a high-pressure side. On the low-pressure side, the air being sucked in through a leak will have a whistle sound. On the high-pressure side, the air being forced out of a leak will have a whoosh sound. Of course, a turbo bearing going bad makes an obvious screech sound.
EPAS Power Steering
Both the PI Sedan and PI Utility use the same power steering system: Electronic Power Assist Steering (EPAS). This is not all-electric steering. Instead, a 12-volt reversible motor uses a toothed belt connected to the steering gear rack to assist (assist-only) the rack and pinion steering. This function is controlled by the Power Steering Control Module (PSCM).
The PSCM is capable of setting and storing DTCs. Depending on the DTC, the PSCM may enter into a failure mode. When this occurs, the failure message will be sent over the High Speed-CAN to alert the driver.
The non-safety critical condition is the Reduced Steering Assist Mode. This may be caused by a low or high battery voltage or a motor over-temperature condition. In this mode, the vary-by-speed aspect of the assisted steering goes to a default level. The steering is still “assisted” but may feel over-assisted at higher speeds and under-assisted at lower speeds compared to the vehicle under normal operation.
The safety-critical condition is called Manual Steering Mode. In this condition, no electrical steering assistance is provided. This mode is triggered when a safety critical condition is detected, or when a reduced steering assist mode has been present for a predetermined number of key cycles. Even in manual mode, the steering feel is better than a hydraulic power steering system that loses a belt or has a hydraulic failure.
Under some maintenance circumstances, the electric motor can get hot. It does not have a separate cooler. The DTC “power steering assist fault” may be set and displayed during an overheating event, but the light may disappear after the system cools down. “Service Steering” means a condition has been detected where the steering assist will be shut down on the next key off. “Service Steering Now” means the electric assist has been shut down.
What conditions would cause the EPAS to overheat? You could be thinking that aggressive EVOC-style driving would do it. Not really. It is primarily due to anything that can cause a bind (of any kind) in the steering: bad ball joints, steering friction or interference, bad rag joint, and rack contamination.
That also means if the inner tie rods are changed, great care must be taken to prevent contamination. The correct lube must be used—the wrong lube must not be used. This whole system, including the steering torque sensor, is very sensitive. Dirt, dust or even the wrong kind of lube will cause a bind. That will cause the EPAS motor to work too hard.
With that in mind, the next diagnosis exercise was a set of pre-loaded, pre-recorded Parameter Identification (PID) based on a PSCM fault that triggered a Service Steering Now motor shutdown. The units of measure are temperature, steering angle direction (left or right), EPAS motor amps and volts, steering shaft torque, degrees of steering wheel angle and steering wheel rotation speed in terms of degrees per seconds. The actions that make the overheat condition are all recorded. Each of these PIDs can help diagnose the Service Steering Now DTC.
UEGO versus Oxygen Sensor
Some vehicles use a different type of upstream oxygen sensor known as a Universal Exhaust Gas Oxygen (UEGO) sensor. The EcoBoost V6 uses the UEGO sensors. This operates differently than a normal oxygen sensor. It provides a more robust (tolerant, less fluctuating) measurement of the air to fuel ratio. It uses the same Nernst cell to measure oxygen content in the exhaust gases.
Instead of comparing oxygen content to the outside air, it compares it to the oxygen content in a self-contained reference chamber. Like the old O2 sensor, it detects lean (more oxygen) and rich (less oxygen) exhaust, and the PCM makes an air-fuel ratio change.
The UEGO does not switch as rapidly or as much as a conventional sensor. At idle, you may not be able to detect any PID current flow (amps) movement at all. How can you tell if the vehicle has a UEGO sensor? Five wires run from the sensor instead of two.
Go to the IDS and check out what the datalogger recorded during the scan. The officer reported a driveability issue: lack of power during acceleration. Compare the seven PID values (volts, psi) at 1 second and then again at 15 seconds as the car is accelerating.
Sure enough, you can see the voltage change in the accelerator pedal position sensor, the cylinder head temperature sensor, and the throttle position sensor. You can see the fuel rail pressure in psi, and the manifold absolute pressure in psi, both change. And see the percentage of short-term fuel trim change. But what you don’t see a change in from the one-second mark to the 15-second mark is the voltage on the throttle inlet pressure.
What does it mean when the UEGO readings on bank 1 are different from bank 2? It sends you to one bank or the other, since the problem is in that bank. PIDs for both sides of the UEGO are the same, perhaps a gasket or head. If the UEGO readings for both sides are the same, it means the fault is a system they have in common, perhaps a MAP sensor.
Within the past few years some entirely new categories of DTC have appeared. The first is the “Service” DTC, designed to help techs correctly service unique systems. No kidding, it will tell you that you pumped the brake pedal too fast when bleeding the brake system. It will tell you that you opened the wrong bleeder or did it at the wrong time. Less insultingly, it will tell you the cam phaser was installed one tooth off.
Another new code is the “Rationality” DTC. This may be set if the PCM suspects one of the sensors is providing bad information even though the reading is within normal limits. Think of it as a gut check. For example, after eight hours of the key-off, the Engine Coolant Temperature (ECT) should be the same as the Intake Air Temperature (IAT). If they are not the same, even though the ECT reading is within normal operating range, the PCM will set a DTC, i.e., something is wrong.
The last of the new DTCs is a “Failure Type.” These are especially associated with passive restraint systems. For these, there is no diagnosis necessary. The five-digit DTC followed by a two-digit failure type code provides information about specific conditions. For example, opens or shorts to ground, or a sensor circuit voltage out of range. If the upfitter removes the front seat to install some gear, there is a specific torque and sequence recalibration procedure to recalibrate with the dual stage airbags.
Many OBD II codes are now (since 2010) non-erasable. In other words, the problem must be fixed, the car driven, and pass a self-diagnosis. The code can’t be cleared by a scan tool and can’t be cleared by disconnecting the battery.
Unlike the Dodge Charger Pursuit and Chevy Caprice PPV tech training, Ford’s NextGen Police Interceptor tech training is fee-based. A charge is required due to contractual clauses with the dealership franchise and Ford intellectual property. The two-day course has a flat fee of $4,200 with a class size ranging from 12 to 18 techs. That is about $280 per tech.
Since it is a flat fee, it is possible for fleet managers and police admin to sit in on the first day. They can audit the vehicle overview, walk around but pass on the diagnostic exercises. Fleet managers will learn a great deal about these new Police Interceptors: new Ti-VCT engines; new 6-speed transaxles; the FWD-default, AWD drivetrain; general PM, and even a bit about upfitting options. They can pass on day two and the serious gear-head diagnostics.
The host department should have one each of the 3.5L (base) V6 P1 Sedan AWD, the 3.7L V6 P1 Utility AWD, and the 3.5L EcoBoost V6 P1 Sedan. If the host department is not running this mix of NextGen PIs, they can borrow units from fleet-oriented dealerships or nearby departments. To get the most out of the investment in training, all three vehicles must be on-hand. These vehicles are for scanning exercises only; none are disassembled.
For more information, contact Chris Keady, Ford Commercial Vehicle Operations at firstname.lastname@example.org. You may also contact your regional government account manager.