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Understanding Toyota's Shift Solenoid Performance Codes


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Toyota's trip logic can be a little tricky if you're not familiar with it's thinking.

Shown courtesy of Gears Magazine.

Published in: Sports, Technology
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Understanding Toyota's Shift Solenoid Performance Codes

  1. 1. PLAYING WITH FIREWhat a Trip!Understanding Toyota’s Shift by Jon Rodriguez www.atra.comSolenoid Performance CodesH ere’s our scenario; An OBD- II Toyota, let’s say a 1999 Camry, comes into your shopwith the MIL lit. You follow standardtest procedures: You connect your scantool, record any codes, clear the codes,and test drive the vehicle to see howlong it takes the code to come back. For this example we’re going tosay the code is the common P0770 —Shift Solenoid E Malfunction. Toyota’scriteria for setting this code is: • Lockup doesn’t occur when driving in lockup range (nor- mal driving at 80 km/h (50 mph), or… • Lockup remains on when it should be off. So we clear the codes and drive theCamry on the freeway to see how longit takes this code to set. After a 10-miletest drive, the MIL doesn’t come backon and you’re scratching your head. You tell the customer the code is What’s a Trip? A trip as defined by Toyota is: “An engine- operation drive cycle that contains all of the necessary conditions for a particular test (monitor) to be performed.”12 GEARS December 2009
  2. 2. What a Trip!intermittent and to drive the car until it until it detects the condition again dur- Check Mode, all diagnosticcomes back. The next day the customer ing the next trip. Then it sets the code codes will be erased instantly.pulls back into the shop with the MIL in memory and lights the MIL. Thison and P0770 in memory. Why did it happens only after the second trip is Now that you understand Checkset with the customer, but not during complete, which means the MIL won’t Mode, you’re ready to use it. Followyour test drive? What a trip! Actually, light until you turn the key off after the these steps whenever an OBD-II Toyotatwo trips. second trip and then restart the engine. comes into your shop with the MIL lit. This situation is a common call to This is why the ratio or solenoid 1. Check codes using yourthe ATRA HotLine. In this edition of performance codes take so long to set. Toyota-compatible scan tool.Playing with Fire, we’re going to cover The problem has to occur on two con- 2. Record any codes in memory.Toyota’s two-trip logic codes and how secutive trips, and then doesn’t appear 3. With the key on, engine offto take advantage of your scan tool’s until the engine is started for the third (KOEO), select Check Modefeatures to diagnose them quickly and time. from your scan tool options.correctly. Does this mean that you have to (Remember that some tools drive the vehicle all this time to diag- will have a different nameWhat’s a Trip? nose the problem? Absolutely not! or location for Check Mode. A trip as defined by Toyota is: Consult your scan tool’s man-“An engine-operation drive cycle that Check Mode ual for more information.)contains all of the necessary conditions Toyota realized that this type of 4. Once you’ve selected Checkfor a particular test (monitor) to be logic can take too much time to diag- Mode, the MIL will flash rap-performed.” This is different than the nose properly, so a little-known diag- idly.SAE definition that we’re all accustom nostic feature was built into Toyota’s 5. Start the engine. Does the MILto but we’re going to use it so we can ECM: Check Mode. turn off?view the following test from the Toyota Most scan tools have an option for • No: Repair the condition thatperspective. Toyotas called Check Mode. Sometimes set the code. For a trip to take place, the vehicle you may see it called by another name • Yes: Switch the scan tool tomust start cold, warm up normally to (Sensitivity Mode, Test Mode or in the data least 160ºF (71ºC). Once you go case of the Ease Scan tool, a square 6. Confirm that the Check Modethrough the necessary driving maneu- button with a checkmark; figures 1 Parameter Identification (PID)vers you’ll need to turn off the key in and 2). indicates on or yes.order to complete the trip. Check Mode does two things to aid 7. Drive the vehicle until the MIL Here’s where Toyota’s trip logic in diagnoses: lights.gets a little tricky. Solenoid electrical 1. Turns all two-trip logic codes 8. Confirm and write down thecodes (P0753, P0758, P0763, P0768, into one-trip logic codes, recurring code.P1818) have one-trip detection logic: regardless of what system is 9. Turn the engine off for at leastWhen the computer detects an elec- being tested. ten seconds to disable Checktrical problem with the solenoid, it 2. Narrows the parameters the Mode.immediately lights the MIL, sets a code computer uses to detect faults so Important: All codes that setin memory, and records Freeze Frame that it’ll set codes more easily. during Check Mode will bedata. During the same cycle, the com- erased automatically whenputer will test the solenoid electrically A few important issues about you turn the engine off.eight times before setting the code. This Check Mode: 10. Follow the manufacturer’susually takes only a few seconds if the • Check Mode clears existing diagnostic tree for repairingproblem is obvious (open or shorted current, pending, and freeze the fault.wire, bad solenoid, etc.) frame codes, so make sure Solenoid performance codes, or you write down any codes By using the Check Mode option,better termed, ratio codes (P0750, in memory before initializing you can solve the mystery of inter-P0755, P0760, P0765, P1815), have Check Mode. mittent codes quickly and accurately.two-trip detection logic: When the com- • Two-trip EVAP codes will Check Mode also works well when testputer first detects the problem, the code remain two-trip codes in driving a freshly rebuilt transmissionis sent to the pending section of the Check Mode. to make sure that a code isn’t going tocomputer and the MIL doesn’t light… • Check Mode disables the come up a day or two after customeryet. The only way to find these codes is Misfire Monitor. delivery. Neither the customer nor theto access the Pending Codes with your • You must record any codes boss like that scenario!scan tool. that set in Check Mode before Special thanks to Roger at Payless Once the computer detects a prob- turning the ignition or scan Transmission and Clutch in Fresno, CAlem the first time, it stops monitoring tool off. When you turn the for his contribution to this article.that particular system during the cur- scan tool or ignition switchrent trip. It won’t actually set a code off, or when you disable14 GEARS December 2009