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For 1990-2009 cars only

DTC P1825 And P1915 Set Defaults To 3rd Gear Start - keywords asembly DTC gear high IMS internal low MIL MH2 MH4 MH6 MY9 mode SES solenoid start switch TCM valve l1 l2 l6 l7 r1 r2 r3 v1 v2 v3 zb

Subject:DTC P1825 and P1915 set, defaults to 3rd gear start

Models:2008 Buick Enclave
2008 Chevrolet Equinox
2007-2008 GMC Acadia
2007-2008 Pontiac G6
2008 Pontiac Torrent
2007-2008 Saturn AURA, OUTLOOK
2008 Saturn VUE
with 6T70/6T75 Automatic Transmission (RPOs MH2, MH4, MH6, MY9)



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Diagnostic codes P1825 and P1915 set, defaults to 3rd gear start.

Poor wire welds on the Internal Mode Switch or internal short to voltage in the Solenoid Valve Asm.(w/Body & TCM).

Recommendation/Instructions:

View the Internal Mode Switch signal readings on the Tech II. Compare with the normal readings (example below).

  1. If switch readings are Low when they should be high, replace the Internal Mode Switch and the Solenoid Valve
  2. If switch readings are High when they should be Low, replace the Internal Mode Switch.

Example: Normal switch Readings

 

Signal

Signal

Signal

Signal

 

A

B

C

P

Park

L

H

H

L

Reverse

L

L

H

H

Neutral

H

L

H

L

Drive

H

L

L

H

M/Drive

L

L

L

L

Example: Switch signal readings Low when they should be High. Replace Internal Mode Switch and the Solenoid Valve Asm.(w/Body & TCM).

 

Signal

Signal

Signal

Signal

 

A

B

C

P

Park

L

L

H

L

Reverse

L _

L _

H

H

Neutral

L

L

H

L

Drive

L

L

L

H

M/Drive

L

L

L

L

Example: Switch signal readings High when they should be Low. Replace Internal Mode Switch

 

Signal

Signal

Signal

Signal

A

B

C

P

Park

L

H

H

L

Reverse

L

L

H

H

Neutral

H

L

H

L

Drive6

H

L

H

L

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.