Toyota Camry Trouble Codes Procedure

Laptop diagnostics
Pulling Trouble Codes doesn't involve a laptop, for better or worse. Getty Images

Like most late-model, 4-cylinder car engines, the 2.2 liter on the 1994 Toyota Camry came standard with an on-board diagnostics computer. But most drivers, like the one who sent in the query below, have a terrible time translating the DTC, or Diagnostic Trouble Codes, produced by the Camry's on-board diagnostics computer. He's not alone. This can be one of the most frustrating systems ever. Ironically, it was designed to make troubleshooting a car's problems easier and more clear, but getting to the point at which you can actually understand the code is another story.

Here is what this owner writes:

I have a 1994 Toyota Camry 2.2 liter 4 cylinder. I recently washed the engine at the car wash and noticed a short time later that the check engine light was on. I have printed the 1994 Diagnostics Trouble Codes for Toyota. Is the check connector under the hood on this model?

And will the check engine light flash 71 times for an EGR system malfunction? What does it do if there is another code, i.e. what kind of flash does it give at the end of the code to let you know that there is another code?

Nothing seems to be wrong. The car runs great and still gets great gas mileage. The light is still on as well. How do I reset it?

 

Let's tackle this one step at a time, starting with the check engine light, or what's also known as the malfunction indicator lamp check.

Checking the MIL

The Malfunction Indicator Lamp (MIL) will sometimes come ON when the ignition switch is turned on but the engine is not running.

(If the MIL does not come on, proceed to troubleshoot the combination meter circuit first.) If everything is functioning properly, the MIL should go OFF once the engine is started.

If the MIL does not go off once the engine is started, that means it has detected a malfunction in the system.

DTC Extraction In Normal Mode

To extract the DTC codes in normal mode, turn the ignition switch ON.

Using a jumper wire or SST, connect terminals TE1 and E1 of the data link connector (DLC) 1 or 2. The data link connector 1 is mounted behind the right strut tower.

Read the DTC codes from the MIL by counting the number of blinks and pauses. When two or more DTC's are present, the lower number code will be displayed first. 

DTC Extraction In Test Mode:

  1. Perform these initial tasks:

    • Battery positive voltage 11 volts or more 

    • Throttle valve fully closed

    • Transmission in park or neutral position

    • Air conditioning switched OFF

  2. Turn ignition switch OFF.

  3. Using a jumper wire or SST, connect terminals TE2 and E1 of DLC 1 or 2. NOTE: The test mode will not start if terminals TE2 and E1 are connected after the ignition switch is turned ON. 

  4. Turn ignition switch ON. 

    • To confirm that the test mode is operating, check that the MIL is flashing when the ignition switch is ON

    • If the MIL does not flash, proceed to the TE2 terminal circuit test under the "Diagnostic Charts"

  5. Start the engine. 

  6. Simulate the conditions of the malfunction as described by the customer. 

  7. After the road test, using a jumper or SST, connect TE1 and E1 of DLC 1 or 2.

  8. Read the DTC on the MIL by counting the number of blinks and pauses. I realize this is not your ideal way to communicate, but it's what they gave you, so roll with it. 

    • When two or more DTC's are present, the lower number code will be displayed first. The example shows codes 12 and 31

  1. After completing the check, disconnect terminals TE1, TE2 and E1 and turn off the display.​

Things to Think About

When vehicle speed is 3 mph or below, DTC 42 (vehicle speed sensor signal) is output, but this is not abnormal. 

  • When the engine is not cranked, DTC 43 (starter signal) is output, but this is not abnormal. 

  • When the automatic transmission shift lever is in the "D", "2", "L" or "R" shift position, or when the air conditioner is ON or when the accelerator pedal is depressed, DTC 51 (switch condition signal) is output, but this is not abnormal.