TEST 3: TCC Lock-up Solenoid Resistance Test
The first test we'll perform on the TCC lock-up solenoid is a multimeter resistance test.
If the TCC lock-up solenoid's resistance isn't within specification, then you've found the cause of the P1735 diagnostic trouble code (DTC).
NOTE 1: The transmission and engine can get very hot. So it's best to perform this test with a cold engine/transmission.
NOTE 2: You can perform this test with the solenoid assembly off or on the vehicle.
These are the test steps:
- 1
Place your multimeter in Ohms mode.
- 2
Unplug the lock up solenoid assembly from its electrical connector.
NOTE: This test is done on the lock-up solenoid's connector AND NOT on the engine wiring harness' pigtail connector. - 3
Measure the resistance between terminal labeled with the #1, in the image viewer above, and the solenoid assembly's body.
NOTE: The TCC lock-up solenoid is Grounded internally thru' the solenoid assembly's case. If the solenoid assembly is still bolted to the transmission housing, you can Ground your multimeter's lead directly on the battery's negative (-) terminal. - 4
The multimeter should register 12-25 Ohms for the resistance value of TCC lock-up solenoid.
Let's take a look at what your test results mean:
CASE 1: Resistance was between 12-25 Ohms. This is the correct and expected test result and generally means that the TCC lock-up solenoid is OK.
Although the TCC lock-up solenoid passed this test, there's still one more we need to do. Which is to manually apply power to the solenoid and see if it clicks. Go to: TEST 4: Applying 12 V To The TCC Lock-Up Solenoid.
CASE 2: Resistance WAS NOT between 12-25 Ohms. Recheck your multimeter test connections and retest. If you still don't get the correct resistance, then the TCC lock-up solenoid is bad and needs to be replaced.
TEST 4: Applying 12 V To The TCC Lock-Up Solenoid
There's a good chance that the TCC lock-up solenoid's resistance is within specification (12-25 Ohms) but the transmission P1735 doesn't go away and the D4 and/or check engine light are blinking/lit on the instrument cluster.
So the next step, after measuring the TCC lock-up solenoid's internal resistance, is to manually apply 12 Volts to terminal #1, of the lock-up solenoid's connector and see if the solenoid clicks.
IMPORTANT: If you've removed the solenoid assembly to test it, you'll need to do one of two things: Bolt it back in place (on the transmission's case). Or Ground the solenoid assembly to the engine (or battery negative post) with a battery jump cable (or this test won't work).
These are the test steps:
- 1
Unplug the lock up solenoid assembly from its electrical connector.
NOTE: This test is done on the lock-up solenoid's connector AND NOT on the engine wiring harness' pigtail connector. - 2
Apply 12 Volts to terminal #1, of the lock-up solenoid assembly's connector, using a jumper wire or a power probe.
- 3
You should hear an audible click when the 12 Volts are applied.
Repeat this test as many times as you need to be certain of your test results.
Let's take a look at your test results:
CASE 1: An audible click was heard when applying 12 Volts. This test result tells you that the solenoid is opening and closing but (there's always a but) this doesn't mean the solenoid is good.
There's a chance that the solenoid is bad, even though it passed TEST 1 and this one (TEST 2). I have some suggestions that may help. For more details, go to: Solenoid Assembly Tested Good But Transmission Still Not Shifting.
CASE 2: An audible click WAS NOT heard when applying 12 Volts. This test result tells you that the TCC lock-up solenoid is bad and needs to be replaced.
Since the TCC lock-up solenoid is part of the lock-up solenoid assembly, you'll need to replace the entire assembly to solve the issue.
