Codes set help

[bdcharrelson]

My 99 DeVille has set two codes: 0741 tcc solenoid circuit performance or stuck off, and 0440 Evap Emiss syst., so two questions.

First, I realize the tcc solenoid is the likely fault, but read elsewhere that a very dirty MAF on which exterior vents are blocked can set this code. Any verification of this?

Second, after checking the obvious gas cap, leaky hoses, etc., have read that the purge valve solenoid has a fuse but I can't locate a fuse so labeled, so what fuse is this solenoid supplied by and where is it located?

Lastly, any other general help regarding troubleshooting these codes will be most appreciated.

[Ranger]

The MAF sensor should have nothing to do with the TCC.

[bdcharrelson]

You are aware that the ecu takes input from the MAF to assist in determining engine load condition,or am I wrong. The thought was that if the ecu thinks the engine is not in a light load condition, tcc will not engage. Same could be true for other sensors involved in this determination. Just trying to avoid tearing in the trans if possible.

[BodybyFisher]

DTC P0741 TCC System Stuck Off

Circuit Description

The PCM controls the torque converter clutch (TCC) solenoid valve pulse width modulation (PWM). The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is applied, the engine is coupled directly to the transmission through the TCC. The TCC slip speed should be near 0.

If the PCM detects high torque converter slip when the TCC is commanded ON, then DTC P0741 sets. DTC P0741 is a Type B DTC.

Conditions for Running the DTC

• No MAF DTCs P0101, P0102, or P0103.
• No TP DTCs P0121, P0122, or P0123.
• No VSS DTCs P0502, or P0503.
• No A/T ISS DTCs P0716, or P0717.
• No TCC Stuck ON DTC P0742.
• No TFP manual valve position switch DTC P1810.
• No TCC PWM solenoid valve DTC P1860.
• The engine run time is greater than 5 seconds.
• The engine is not in fuel cut off.
• The TFP manual valve position switch indicates D4.
• The transmission gear ratio indicates 2nd, 3rd, or 4th gear.
• The transmission fluid temperature is -18-130°C (0-266°F).
• The throttle angle is greater than 8 degrees.
• Delivered torque is between 43-202 N·m (32-150 lb ft).
• The TCC solenoid valve is commanded ON at maximum duty cycle.

Conditions for Setting the DTC

TCC slip speed exceeds its limit for a given torque for 5 seconds.

Torque (lb ft) / Slip Speed Limit (RPM)

32 / 72

64 / 88

96 / 200

128 / 248

160 / 256

Action Taken When the DTC Sets

• The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
• SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the driver information center (DIC).
• The PCM inhibits TCC engagement.
• The PCM inhibits 4th gear if the transmission is in hot mode.
• The PCM stores DTC P0741 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

• The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
• A scan tool clears the DTC from PCM history.
• The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
• The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids

• Inspect the transmission fluid level.
• The transmission may be in hot mode. Inspect the transmission fluid lines to the radiator. The lines may be pinched, plugged or twisted

[BodybyFisher]

4T80E MH1 SES Light On DTC P0741 ( TCC Stuck Off ) - kw apply converter fluid pressure shift slip torque transmission valve #PI02103 - (May 17, 2004)

4T80E MH1 SES Light On DTC P0741 (TCC Stuck Off) When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:

Condition: Customer may complain of SES light on, SES light on and chuggle or surge. Diagnostics may show excessive TCC slip speed and DTC P0741 will be current code stored.

Cause: Excessive TCC Slip Speed, TCC may have partial apply fluid pressure or no apply fluid pressure. If excessive slip speed noted and condition/cause cannot be diagnosed by using DTC P0741 diagnostic chart, suspect worn seals from slippage of the drive sprocket bearing inner race on the drive sprocket.

Recommendation/Instructions:

Correction: The transmission must be removed from the vehicle. Remove the side cover, upper valve body, case cover, drive chain, drive and driven gear. Inspect the drive sprocket support (Item 400) for wear on the outer radius. Inspect the following seals for wear;

#034 ........................ p/n 24201992 .......Seal, Case cover to drive sprocket

#035 ........................ p/n 24201991 .......Seal, Case cover to turbine shaft

The wear pattern will be evidenced by an uneven appearance of the inner diameter white seal surface, in some instances the inner seal may be torn away from the seal shell (Figures 2 thru 4, and 7) or the seal surface may be uneven in appearance. Compare a new seal (Figure 6) versus the installed seal (Figures 2 thru 4 and 7). The white seal surface should be an even width around the inner diameter (Figures 8/9). Seal damage will allow TCC apply fluid to drain into the channel plate, causing excessive slippage of the TCC under certain load conditions and eventually cause no TCC apply.

In addition the following seals should be replaced.

#409 ........................ p/n 08679881 .......Drive sprocket oil seal

#412 ........................ p/n 08686052 .......Seal, turbine shaft O-Ring

[bdcharrelson]

Wow! Massive information and thanks. Was hoping for something like "experience shows its usually the tcc solenoid, easily replaced by pulling the pan and valve body" but that's the way it goes. Thanks again for the detailed response.

[BodybyFisher]

The problem is.... 1) is it the TCC solenoid, its wiring, or 2) is it the torque converter or seals as described above, or 3) is it caused by a P1860 code (see Logan's thread)

It is not easy to diagnose this here, it really needs a Tech 2

The P0741 is a fairly common code, it means that the TC is slipping, the cause of that slipping must be determined. I am about to yank my engine out, when I do, I plan to replace the TC, as it has 125K on it. When I was in my side pan, I replaced my TCC, ISS and Pressure solenoids, as PM.

Sorry I could not be more helpful. The problem is that most transmission shops will look to do a full rebuild. See if you can get someone to diagnose it, maybe a compliant caddy dealer to tell you exactly what is causing

[BodybyFisher]

See this thread from Logan for more on P0741, its not 100% relavant because it involves the P1860, but Logan is very knowledgable

http://caddyinfo.ipbhost.com/index.php?showtopic=12067