2001 Isuzu Rodeo Question Brake Pedal Travel

Tiny
HULADICK
  • MEMBER
  • 2001 ISUZU RODEO
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 21,000 MILES
This Rodeo has 4 wheel ABS. Sometimes while stopping, the pedal will go to the floor. Then I pump the pedal and the wheels lock up and stops very quickly. After that, everything acts normally for a while and it will do it again.

I cannot get it to repeat itself in the presence of a mechanic. Hard to troubleshoot when it won't fail all the time. Thanks for any help.
Sunday, July 13th, 2008 AT 5:46 PM

13 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Any dash lights come on when it happens?
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Sunday, July 13th, 2008 AT 6:10 PM
Tiny
HULADICK
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No dash lights. Just the pedal going to the floor.
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Sunday, July 13th, 2008 AT 8:03 PM
Tiny
MERLIN2021
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The combination valve may be defective if the dash light didn't come on during the problem. If this is bad pressures between front and rear is affected, and pedal hieghts will change until the valve centers.
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Monday, July 14th, 2008 AT 9:06 AM
Tiny
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Thanks Merlin.

If the combination valve was bad, would I still feel brakes at either front or rear? When my problem happens, I have no brakes at all until I pump it. Then they lock up.
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Monday, July 14th, 2008 AT 11:34 AM
Tiny
MERLIN2021
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If the combination valve is bad, we can test it! Open a bleeder at the rear and have a friend turn the key on wait until the warning light goes out, open bleeder, push pedal down slowly and hold, close the bleeder, did the warning light go on? Then repeat this test at a front bleeder, if thelight does not go on, valve is bad! The other possibilty is contaminated fluid, if tranny or motor oil was added to the master cylinder, you will also have these problems, and it will get worse until all parts made of rubber are replaced, oil swells the seals and softens them. Test the fluid by removing some from the master and putting it in a cup of water. Swirl it, the color should turn milky white, with NO OIL beads in it.
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Monday, July 14th, 2008 AT 4:51 PM
Tiny
CAGRIFF2
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Correction: It has ABS light coming on when this happens. EGR valve is bad/going bad, Could this have anything to do with it?
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Thursday, August 7th, 2008 AT 4:25 PM
Tiny
MERLIN2021
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Not likly that the EGR has anything to do with it. Read the codes like this...post em and we go from there. OK" ANTI-LOCK -2001 Isuzu Rodeo LS
Page 1 of 1
RETRIEVING DIAGNOSTIC TROUBLE CODES

Using Scan Tool
Connect scan tool to Data Link Connector (DLC). See Fig. 1 . Following scan tool manufacturer's instructions, select appropriate mode to view DTCs. If DTCs retrieved, see DIAGNOSTIC TROUBLE CODE INDEX table. Identify DTC and perform specified diagnostic procedure. See DIAGNOSTIC
TESTS . After repairs, DTCs must be cleared. See CLEARING DIAGNOSTIC TROUBLE CODES . If no DTCs are retrieved, diagnose by symptom. See SYSTEM TESTS .

Using ABS Warning Light
1.When ABS warning light remains illuminated, EHCU will store DTCs and disable ABS system. If DTCs are not displayed, wiring harness from EHCU to ABS warning light may be disconnected. Check and repair harness if necessary. 2.Ensure ignition is off and brake pedal is released. Using jumper wire, jumper Data Link Connector (DLC) terminals No. 4 and 12. See Fig. 1 . Turn ignition on. DTC is displayed by flashing ABS warning light. See Fig. 2 . 3.A stored DTC is displayed 3 times, each being separated by a 3.2 second pause. If multiple DTCs are set, second DTC will follow after first DTC is displayed a third time. All DTCs contain 2 digits. First digit of DTC is identified by a series of .4 second flashes. After a 1.2 second pause, second digit of DTC will follow in another series of .4 second flashes. If no DTCs have been stored, ABS warning light will repeat DTC 12 (system normal). 4.If DTCs are retrieved, see DIAGNOSTIC TROUBLE CODE INDEX table. Identify DTC and perform specified diagnostic procedure. See DIAGNOSTIC TESTS . After repairs, DTCs must be cleared. See CLEARING DIAGNOSTIC TROUBLE CODES . If no DTCs are retrieved, diagnose by symptom. See SYSTEM TESTS .
Fig. 1: Identifying Data Link Connector Terminals

Fig. 2: ABS Diagnosis Using ABS Warning Light


http://www.2carpros.com/forum/automotive_pictures/62217_ABS_1.jpg

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Friday, August 8th, 2008 AT 3:43 PM
Tiny
JAWONG71
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Hi Merlin2021,

I do have a question, the clearing of the codes, it mentions to jumper terminal A to terminal H of the ALDL/DLC. Is that different than what the Pin 4 to Pin 12 for reading the codes?

I have an obd2 scanner but it won't read the ABS codes. The manufacture says the abs update will not work on my rodeo.
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Tuesday, November 24th, 2009 AT 3:39 PM
Tiny
MERLIN2021
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I have found two ways, one is sure to be right.
1. With the ignition off jumper pins 4 &12 of the DLC connector 2. Switch the ignition on & allow the ABS lamp to flash at least once before proceeding. 3. Depress the brake pedal by hand until you hear the solenoid click, then release the pedal.  Repeat  8 times within 3 seconds.  After the 8th pedal cycle the ABS lamp stops flashing, lights for 1 second, then begins flashing code 12 (no codes).  Memory is erased once code 12 flashes 4 times.  Shop key data incorrect & missing important steps to clear fault code. Please revise.
Second way:
Ensure ignition is off and brake pedal is not depressed. Using jumper wire, jumper DLC terminals No. 4 and 12 together, and within 3 seconds, rapidly depress and release brake pedal 6 or more times. See Fig. 1 . DTCs will not be cleared if brake pedal is not depressed within 3 seconds of jumping DLC terminals.


http://www.2carpros.com/forum/automotive_pictures/62217_1_49.jpg

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Wednesday, November 25th, 2009 AT 7:16 AM
Tiny
JAWONG71
  • MEMBER
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Hi Merlin21,

I finally got around to jumpering the pins. What confuses me is that all reading material says the ABS lamp will flash, but the only lamp that flashes is the AirBag lamp. The code that is returned it 12 assuming that I counted correctly.

But still the ABS lamp on the top of the dash is fully lit. The only thing I can think is that the information here is for a 2001 Rodeo, whereas I have a 1996 model.

I'll try and take a picture to show the dash when I get another chance to work on the vehicle.
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Wednesday, December 2nd, 2009 AT 10:21 AM
Tiny
MERLIN2021
  • MECHANIC
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Brakes problem
2001 Isuzu Rodeo Question 6 cyl Four Wheel Drive Automatic 210, 00 miles
This is what I was working on, I did not see 1996? Did I miss something? On 1996 you use the same pins and read the ABS light, NOT Air bag. Same as on 2001! Check your fuse. And connectors to abs system.
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Thursday, December 3rd, 2009 AT 2:28 PM
Tiny
JAWONG71
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Merlin2021,

I finally go the pins jumper'd correctly, I was able to get several codes out, but I believe the latest code that is repeating itself is 32, the history codes were several, but after clearing those, just 32 kept coming up.
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Tuesday, December 29th, 2009 AT 12:47 PM
Tiny
MERLIN2021
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DTC 32: PUMP MOTOR FAILURE 1. Turn ignition off. Disconnect coil integrated module harness connector. Measure voltage between ground and coil integrated module harness connector terminal No. 1 (White/Green wire). If battery voltage is present, go to next step. If battery voltage is not present, check condition of ABS fuse (60-amp) located in engine compartment fuse block. Check White/Green wire between fuse and coil integrated module for open or short to ground. Repair as necessary. After repairs, go to step 5. 2. Ensure harness from Electronic Hydraulic Control Unit (EHCU) unit is connected to coil integrated module connector. Go to next step. 3. Check condition of harness from EHCU. If harness is okay, go to next step. If harness is not okay, repair as necessary. After repairs, go to step 5. 4. Measure resistance between EHCU connector pins No. 1 and 2 (component side). If resistance is.2-1.0 ohm, replace coil integrated module. If resistance is not.2-1.0 ohm, replace EHCU. 5. Reconnect all components. Ensure all component are properly installed. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Verify system operation. See SYSTEM OPERATION CHECK under TROUBLE SHOOTING.
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Tuesday, December 29th, 2009 AT 1:11 PM

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