Engine/Tranny Systems, and Sensor Info/Troubleshooting Guide

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Dodge ram spec charts and wiring

Full line wiring along with all the specs for your ram. Its a PDF file that you click through to find your year along with any info your checking for.

http://www.rambodybuilder.com/year.pdf

 

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Oxygen (O2) Sensor Info:

3rd generation rams have 4 total O2 sensors (Exception: 2003 dodge rams are the red headed step child, then only have 2). They are located in the driver and passenger exhaust manifold.

2 upstream, and 2 downstream. The upstream ones are right after the header (or in the tail end of the header if you have long tubes, while the downstream ones are located aft of the catylitic converter (CAT).

The upstream O2 sensors help determine, in real time, if the air/fuel ratio of the engine is rich or lean. Now since they are in the exhaust, they do not directly measure the air or the fuel entering the engine. But when information from sensors is added with information from other sources, it can be used to indirectly determine the air-to-fuel ratio.

They downstream sensors will only read your catylitic converter efficiency, and thus are only really for emissions. They will shoot a fail code if your cat fails or you install a high flow cat, or delete the cat entirely.

There are also two different types of O2 sensors. Heated and unheated.

The unheated sensors only last about 50K miles, and require 1-3 minutes to heat up to operating temperature. They only have two wires coming from them.

The heated terminals last up to 100K miles, and differ in that they contain 4 wires. 2 of the wires are for the heating element which heats the sensor up fast so it can work properly without waiting for the exhaust to heat up.

What does this mean for you:

Ok so when you start your vehicle, your ECU regulates your air/fuel ratio based on a preset 14.7/1 air to fuel ratio. There's no inputs or changes, it stays the same. This is called an open loop.

When your o2 sensors heat up and start sensing the oxygen levels in your exhaust, the information is added to other sensors, sent to your ECU and converted into data to regulate your Air/Fuel ratio. Things like elevation, temperature and air density can change the way your engine runs, so this information is vitally important. When all these sensors are working together and the information is being sent to your vehicles computer, it's called a closed loop. If you start your vehicle and listen to the engine, you can usually hear when it changes from an open to closed loop. It happens pretty quick if you have a newer vehicle.

How can they go bad: Now these sensors are directly in the path of your exhaust... so eventually they will go bad. Sometimes the heating element will fail, or the sensor will get clogged (especially if your running rich), which will be noticeable because the sensor will be black with thick soot.

If you install long tube headers, or high flow catalytic converters, or remove the cats, the sensors will show an increase in exhaust and oxygen and thus give you a fail code. You can install spark plug non-foulers to help this (they fit between the exhaust manifold and the sensor). These will move your O2 sensor out of the direct path of the exhaust so they wont read a failing cat.

If you only have 2 sensors (2nd gen rams and older vehicles) the sensor fail code will read Bank 1 Sensor 1 (front sensor), or Bank 1 Sensor 2 (aft sensor).

If you have 4 sensors, Bank 1 is the passenger side exhaust/header pipe, and bank 2 is the drivers side exhaust/header pipe.

So Bank 1 Sensor 1 (Passenger side front sensor), Bank 1 Sensor 2 (Passenger side aft sensor, Bank 2 Sensor 1 (Driver side front sensor), Bank 2 Sensor 2 (Driver side aft sensor).

If you do end up throwing a code, refer to this site for the type of error your receiving:

OBD-II Check Engine Light Trouble Codes

 

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EGR Valve (Exhaust gas Recirculation) Info:

The EGR valve, or Exhaust Gas Recirculation valve, is a vacuum controlled valve (or computer controlled on certain vehicles) which allows a specific amount of your exhaust back into the intake manifold. This exhaust mixes with the intake air and actually cools the combustion process. Cooler is always better inside your engine. The exhaust your EGR valve recirculates also prevents the formation of Nitrogen related gases. These are referred to as NOX emissions, and are a common cause for failing emissions testing.

What does this mean for you: The EGR valve will last approximately 100K miles and helps your engine for emissions.

How can it go bad: As it operates, carbon and deposits can become stuck to the valve, and your EGR valve can get stuck open or closed, causing NOX gases to build up inside your engine. You'll know if your EGR valve is stuck or malfunctioning because your car will experience symptoms like rough idle and bucking on accelertaion.

 

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Coolant Temperature Sensor (CTS) Info:

The coolant temperature sensor is a thermistor (a resistor which varies the value of its voltage output in accordance with temperature changes). The change in the resistance values will directly affect the voltage signal from the water thermosensor. As the sensor temperature decreases, the resistance values will increase. As the sensor temperature increases, the resistance values will decrease.
The coolant temperature sensor lets the engine control computer know what the engine temperature is by gathering information from the engine coolant temperature.

What does this mean for you: The Coolant Temp Sensor lets your engine and computer know the temperature of the coolant, and make adjustments, and is critical to many PCM functions such as fuel injection, ignition timing, variable valve timing, and transmission shifting.​

How can it go bad: The sensor can corrode from coolant, and water can also slowly leak through to the wires. If it goes bad it should trip a trouble code, but if your vehicle starts using more fuel than usual, starts having trouble starting when the engine reaches normal operating temperature or you notice black smoke coming out from the exhaust tail pipe, it is very likely that these symptoms are related to a bad coolant temperature sensor. The sensor is normally located on the engine block right next to the coolant hose.​

 

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Knock Sensor Info:

The knock sensor responds to spark knock caused by Pre-detonation of the Air/Fuel mixture. As the flame front moves out from the spark plug ignition point, pressure waves in the chamber crash into the piston or cylinder walls resulting in a sound known as a knock or ping. This is caused by using a fuel with a low octane rating, overheating, or over advanced timing. Sometimes it can be caused by hot carbon deposits on the piston or cylinder head that raise compression. A knock sensor is comprised of Piezoelectric materials; Crystals that when impacted, generate a voltage (same idea as a BBQ ignitor). This voltage is monitored by the computer, and when an irregularity is detected, the computer corrects timing in VVT (variable valve timing) engines, or triggers a DTC Diagnostic Trouble Code) in older vehicles.

What does this mean for you: A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.

How can it go bad:
The only sign is if it goes bad it should trigger the check engine light, you shouldn't see a loss in peformance in engine.

 

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Throttle Positions Sensor (TPS) Info:

Important: 3.7L and 4.7L engine have TPS, while the 5.7L has an integrated TPS.

The throttle position sensor (TPS) keeps the PCM informed about throttle position. The PCM uses this input to change spark timing and the fuel mixture as engine load changes.

What does this mean for you: When you push your gas pedal down, your TPS tells your engine to go faster.

How can it go bad:


You will notice your vehicle do the following:

• Bucking and jerking of the car.
• Idle surging of the car.
• Sudden stalling of the car engine.
• Hesitation while the driver of the car is trying to accelerate.
• Sudden surge in car's speed while driving on the highway.

What Happens with a Bad Throttle Position Sensor?

The data provided by TPS is invaluable for proper startup, idle and easy throttle response of the car. These operations are affected when a bad throttle position sensor feeds erroneous data to the car's computer. Because of this, the following can occur:

• Engine Malfunction Indicator Light (MIL) is turned on.
• The driver of a car experiences difficulty while changing gears.
• The fuel economy of the car drops drastically.
• Causes difficulty in setting base-ignition-timing of the car.

 

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Crankshaft Position Sensor (CPK) Info:

This sensor is also known as the Engine Speed Sensor (ESS). It provides data that enables the computer to know which cylinder should be fired at the crankshaft's present position. This sensor is essential to ensuring that the engine cylinders are always fired in the correct order. The Crankshaft Position Sensor (CPK) is always located somewhere on the engine in close proximity to the crankshaft, usually near the harmonic balancer or in the engine block aligned with a toothed wheel connected to the crankshaft. The CPK provides the data that is used to compute the engine's revolutions per minute (RPM), which is essential for proper transmission gear selection in relationship to vehicle speed and load.

What does that mean for you:

The Crankshaft Position Sensor basically just lets your vehicles computer know the speed and position as your engine turns over.

How can it go bad:

If the vehicle engine is experiencing cylinder misfires, the CPK may not be providing the computer with accurate information on piston position. If the vehicle hesitates during acceleration, the CPK may not be providing cylinder position data to the computer fast enough to fire the appropriate cylinder to accelerate the vehicle in response to driver input. The most serious indication of CPK malfunction is intermittent start, and eventually no start. When the sensor fails, the computer will register a malfunction code and illuminate the check engine light on the instrument panel. There may be an indication of sensor failure due to defective electrical connections such as high resistance, or an open condition in the circuit going to the sensor or returning to the vehicle engine control module.

 

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Camshaft Position Sensor (CPS) Info:

Air Temperature Sensor (ATS) Info:

Output Shaft Speed Sensor (OSS) Info:

Manifold Pressure Sensor (MAP) Info:

Coolant Thermostat and complete Cooling system Info: