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I was wondering if anyone can help me with a problem, I have a 2004 caddilac SRX, with the 4.6 Northstar, rear wheel drive, I have problmes with hard shift, on all gears, they go into all the gears but it is hard, the engine light is on and receive the codes PO 1825 and PO 1826 power train codes, P1825 - Internal Mode Switch - Invalid Range and P1826 - Internal Mode Switch Circuit C - High just wanted to know if anyone else has come across the codes before with a similar problem



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Looking at the range of codes that include P1825 and P1826,

P1815 Transmission Range Switch - Start In Wrong Range

P1816 TFP Valve Position Sw. - Park/Neu. With Drive Ratio

P1817 TFP Valve Position Sw. - Reverse With Drive Ratio

P1818 TFP Valve Position Sw. - Drive Without Drive Ratio

P1819 Internal Mode Switch - No Start\Wrong Range

P1820 Internal Mode Switch Circuit A Low

P1822 Internal Mode Switch Circuit B High

P1823 Internal Mode Switch Circuit P Low

P1825 Internal Mode Switch - Invalid Range

P1826 Internal Mode Switch Circuit C - High

P1831 Pressure Control (PC) Solenoid Power Circuit - Low Voltage

P1832 Pressure Control (PC)/Shift Lock Solenoid Control Circuit High Voltage

P1833 A/T Solenoids Power Circuit - Low Voltage

P1834 Torque Converter Clutch (TCC)/Shift Solenoid (SS) Control Circuit High Voltage

it looks like one of your mode switches is shorted to the power line. I know little about your particular automatic transmission so someone else will need to step in here to tell you whether this is a likely wiring problem or whether you need to replace some transmission innards, and how much of a problem it is to fix.

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A P1825 DTC will result in the TCM commanding maximum transmission line pressure as a safety measure for self protection. That pretty much explains the "hard shifts."

From a DIY point of view you're pretty much limited to removing, inspecting, and reseating the 20 pin electrical connector on the transmission. If you don't have a connector or wiring harness problem the odds favor the shift position switch inside the transmission being bad.

That's a job for the transmission shop. It involves dropping the exhaust, transmission pan and such.



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I need to find the trouble codes for a 1991 caddy eldoredo My car runs but will did all of a sudded Thanks Donna

1. Turn ignition ON

2. Press WARMER and OFF simultaneously for a few seconds until trouble codes show up on driver information center.

3. Write them down

4. Turn ignition OFF

5. Repeat the procedure if you missed some codes.

6. Post here what you found.

The saddest thing in life is wasted talent

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