Tip & How-To about Toyota Camry

The Check Engine Light - Basics!

Today's cars are controlled by a Powertrain Control Module (PCM), your engine's computer. To repair or modify your car's performance, you need a scantool to communicate with the PCM.

The Check Engine Light, the "Malfunction Indicator Light"or "MIL" for short, is on because your vehicle's computer self-diagnosed a fault that could cause your vehicle's emissions to increase. It doesn't necessarily mean your vehicle is polluting or has a serious problem, but it might. So the light is on to let you know something is amiss that needs your attention.

Trouble is, you don't know WHAT the trouble might be. It might be something that could lead to a break-down or cause expensive engine damage, or it might be something minor like a loose gas cap (yes, the on-board diagnostic on 1996 and newer cars can even detect a loose, missing or leaking gas cap).

There's no way to know what the problem is without talking to your vehicle's computer.

How do you do that? By plugging a diagnostic scantool into your vehicle's diagnostic connector, usually found under the dash near the steering column. These tools unlock the secrets that have turned on your Check Engine Light and tell you the nature of the problem.

Yet these tools are only the messenger. It's up to you to combine information from the tool with knowledge of how the electronic system in your engine works to make an accurate diagnosis.

Read on as I unleash more Automobile Diagnostic tips.

Cheers.

Sholly-NG

Posted by on

Cars & Trucks Logo

Related Topics:

Related Questions:

1 Answer

Where is the automatic transmission modular located on 2001 buic centry


Do you mean the transmission control module ? It is incorporated into the engine control module . PCM - powertrain control module .

Powertrain Control Module (PCM) (L36/L67)
Left front of the engine compartment, inside the air cleaner assembly
Engine Controls Component Views in Engine Controls - 3.8L
Powertrain Control Module Connector End Views in Engine Controls - 3.8L
Powertrain Control Module (PCM) (LG8)
Left front of the engine compartment, inside the air cleaner assembly

Oct 04, 2015 | Cars & Trucks

1 Answer

what is a control module


I small computer box that performs engine or transmission or accessory functions. for example: ecm electronic control module. or tcm transmission control module. or pcm powertrain control module. or lcm lighting control module.or bcm body control module

Apr 16, 2015 | Cars & Trucks

1 Answer

loss of communication with the tcm and pcm


The onboard computer, or Powertrain Control Module (PCM),is the brains of the engine control system, so when the brain is not functioning correctly neither is the engine or anything else that the microprocessor controls - which may include the charging system, transmission, various emission controls and communications with other onboard control modules. Once a diagnosis has been made (and we emphasize the word diagnosis), then and only then should the PCM be replaced.
P0600....Serial Communication Link

P0601....Internal Control Module Memory Check Sum Error

P0602....Control Module Programming Error

P0603....Internal Control Module Keep Alive Memory (KAM) Error

P0604....Internal Control Module Random Access Memory (RAM) Error

P0605....Internal Control Module Read Only Memory (ROM) Error

P0606....ECM/PCM Processor

P0607....Control Module Performance

P0608....Control Module VSS Output 'A'

P0609....Control Module VSS Output 'B'

P0610....Control Module Vehicle Options Error

If you see any of these codes when diagnosing the vehicle with a code reader or scan tool, it may mean the PCM has failed and must be replaced. Additional diagnostic tests will usually be necessary to confirm the problem is really the powertrain control module and NOT something else. Refer to the OEM diagnostic charts for what these tests are. Usually it involves checking certain inputs to the PCM to see if it outputs the correct response. No response or an incorrect response usually means the PCM is defective and needs to be replaced.
All too often, technicians tend to blame that which they understand least. If an engine is not running right and the cause is not obvious, they may blame the computer. Throwing parts at a problem in an attempt to solve it may be good for the parts business, but when a customer brings a PCM back because it failed to fix their problem, nobody wins. Warranty returns on complicated and expensive components like powertrain control modules are an ongoing problem that costs everyone money.
UNNECESSARY POWERTRAIN CONTROL MODULE RETURNS. Over 50 percent of PCMs that are returned under warranty (either because the PCM failed to fix a performance problem or because the engine did not run properly after it was installed) have nothing wrong with them! So it is obvious a lot of people are swapping computers to see if a different PCM will fix their problem.
The trouble with returns is if the PCM has been on the car, you have no way of knowing if it is still "good" or not. Somebody may have crossed up some wires, zapped the PCM with too much voltage or who knows what? The computer needs to be tested and verified before it can go back on the shelf and be sold to somebody else.
Unfortunately, there is no easy way of doing that in a parts store. The PCM has to be hooked up to a sophisticated simulator that exercises all of the computer's input and output circuits to make sure it works correctly - which means the PCM has to go back to the supplier, be retested, and if no fault is found, repackaged and put back into stock.
Be warned, though, that many parts stores have a policy of "no returns or refunds on electronic components."

Mar 20, 2014 | 2005 Lincoln Navigator

1 Answer

2001 Dodge Dakota Engine Light


below is coped directly from Chrysler. sorry but if you have that code you need a PCM

Symptom:

P0601-PCM INTERNAL CONTROLLER FAILURE
POSSIBLE CAUSES
POWERTRAIN CONTROL MODULE
TEST ACTION APPLICABILITY

1 NOTE: This DTC indicates an internal PCM problem.
If there are no possible causes remaining, view repair.

All
Repair
Replace and program the Powertrain Control Module in accordance
with the Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 2.
38
COMMUNICATION

Mar 25, 2009 | 2001 Dodge Dakota

1 Answer

plenty battery power, but engine won't turn over


POWERTRAIN CONTROL MODULE (PCM)
The Powertrain Control Module (PCM) is a preprogrammed, dual
microprocessor digital computer that receives various input signals from sensors and switches, and provides the necessary signals to output devices to achieve optimum engine performance conditions.


The immobilizer is inside the PCM. But if your engine does not crank, then the relais in the PDC (power Distribution Center), the Relay in the starter itself too has to be checked.

Mar 23, 2009 | 1996 Jeep Grand Cherokee

Not finding what you are looking for?

1,369 people viewed this tip

Ask a Question

Usually answered in minutes!

Top Toyota Experts

yadayada
yadayada

Level 3 Expert

75197 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22095 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

7782 Answers

Are you a Toyota Expert? Answer questions, earn points and help others

Answer questions

Loading...