Tundra transmission problem

The MIL was on in this Tundra pickup, and we pulled a manufacturer-specific transmission code from it:

4/12/2009 15:37:38

Toyota Tundra 2005


	Pressure Control Solenoid 'D' Electrical

	Freeze Frame (Frame 0) for DTC P2716	

	Absolute Evaporative System Vapor Pressure: 100 %
	Absolute Load Value: 32 %
	Absolute Throttle Position D: 25 %
	Absolute Throttle Position E: 41 %
	Absolute Throttle Position: 21 %
	Air Flow Rate From Mass Air Flow Sensor: 2.75 lb/min
	B1S2 O2 Sensor Output Voltage: 0.800 V
	B2S2 O2 Sensor Output Voltage: 0.780 V
	Calculated Load: 31 %
	Commanded Equivalence Ratio: 1.002 Lam
	Commanded Throttle Actuator Control: 21 %
	Control Module Voltage: 13.85 V
	Coolant Temperature: 187 F
	Engine RPM: 1410 r/min
	Fuel System Status Bank One: Closed Loop
	Fuel System Status Bank Two: Closed Loop
	Ignition Timing Advance for #1: 25.5 deg
	Intake Air Temperature: 50 F
	Long Term Fuel Trim Bank One: 4.68 %
	Long Term Fuel Trim Bank Two: 3.90 %
	Relative Throttle Position: 5 %
	Short Term Fuel Trim Bank One: 0.00 %
	Short Term Fuel Trim Bank Two: 0.00 %
	Vehicle Speed: 37 MPH
The problem had evidently occurred while the truck was being driven around, and had been out for a while [up to full running temp]. Charging circuit was good, holding at 13.8+ volts; load was fairly light and the fuel trims and a/f look healthy.

The service manual led us right to the problem area: open or short in a solenoid drive circuit, from the ECM to the electronically-controlled automatic transmission. Right away I thought "bad wire or connector".

The problem was obvious as soon as the 15-pin transmission control connector was pulled -- a significantly crapped-up and corroded area around some of the pins, worst around the connection for the "SLT pressure control solenoid" in question. I was hoping we could just clean it up and put it back together and fix the problem.

[Click the image for a larger detail.]

Alas, that was not to be. Examining the male half on the transmission with an inspection mirror showed that the pin in question was completely *missing* -- broken off and eaten by the female half of the connector. After scraping away a little more of the crud I could see the bottom of what was left of it sitting inside the female half.

[Click the image for a larger detail.]

The transmission-side half of the connector is bolted in and sealed with an O-ring and clearly below transmission fluid fill-hole level, so trying to extract it would have meant draining some fluid first. And if the solenoid in question was bad, getting to it involves taking off the pan, fluid pickup filter, and entire valve body OUT of the transmission. The solenoid is one of about eight that fit into the valve body. Solenoid aside, the connector was not something we were going to fix today or likely at all -- off to the dealer later in the week.

The connector seems designed with the intent of keeping splash out of it, since it's right there exposed to everything thrown up from the road, so I'm not sure how water got in [if that's even the cause]. Perhaps the little gasket around the wire where it comes into the outer connector leaked, letting the infamous New England winter salt-solution seep down into there.

_H* 090412